here - High Energy Physics Group

Transcription

DOE/SC-0032
Cover art: False-color high resolution FESEM image of a superconducting Nb3Sn filament fractured to reveal microstructure (Peter J. Lee, The Applied Superconductivity Center, University of Wisconsin-Madison).
TABLE OF CONTENTS
DOE-High Energy Physics, D. Sutter and B. Strauss
•
Introduction...................................................................................................... 5
UNIVERSITY PROGRAMS
Columbia University, T.C. Marshall
•
Experimental Research on Microwave Inverse Cerenkov, Inverse FEL, and Wake
Field Accelerators .............................................................................................. 9
Cornell University, R. Talman
•
Accelerator Simulation Code Development .........................................................13
Florida A&M University, R.L. Williams
•
Electron Beam Transport in Advanced Plasma Wave Accelerators........................17
Florida State University, S.W. Van Sciver
•
Liquid Helium Fluid Dynamics Studies ................................................................20
Indiana University, S.Y. Lee
•
Beam Dynamics and Beam Manipulations ..........................................................23
Massachusetts Institute of Technology, C. Chen
•
Periodically Focused Intense Charged-Particle Beams .........................................27
Massachusetts Institute of Technology, R. Temkin
•
17 GHz High Gradient Accelerators Research .....................................................31
Michigan State University, R.C. York
•
Investigations of the Dynamics of Space Charge Dominated Beams ....................36
Michigan State University, M. Berz
•
Research Activities at MSU Beam Theory Group .................................................39
National Institute of Standards and Technology, L. Costrell
•
Instrumentation Standards ...............................................................................50
National Institute of Standards and Technology, J. Ekin
•
Electromechanical Properties of Superconductors ...............................................52
Naval Research Laboratory, S.H. Gold
•
Development of a Thermionic Magnicon at 11.4 GHz..........................................55
Naval Research Laboratory, I. Haber
•
Focused Transport of Space-Charge-Dominated Beams ......................................59
Naval Research Laboratory, P.A. Sprangle
•
High Energy Laser-Driven Acceleration Based on the Laser
Wakefield Accelerator.......................................................................................62
Ohio State University, E.W. Collings and M.D. Sumption
•
Materials, Strands, and Cables for Superconducting Accelerator Magnets.............66
Princeton University, R.C. Davidson
•
Nonlinear Dynamics and Collective Processes in Intense
Charged Particle Beams.....................................................................................71
Princeton University, N. Fisch and G. Shvets
•
Advanced Accelerator Studies ...........................................................................75
Stanford University, R.L. Byer
•
The Laser Electron Acclerator Project at Stanford University ...............................78
STI Optronics, Inc., W.D. Kimura
•
Staged Electron Laser Accelerations (STELLA) Experiment ..................................82
Texas A&M University, P. McIntyre and A. McInturff
•
High-field Superconducting Magnet R&D at Texas A&M University.......................86
University of Texas at Austin, T. Tajima
•
Laser Wakefield Acceleration Research ..............................................................89
University of California - Berkeley, J.S. Wurtele
•
Advanced Accelerator Concepts at UC Berkeley ..................................................94
University of California – Los Angeles, D.B. Cline
•
Advanced Accelerator Research.........................................................................97
University of California – Los Angeles, C. Joshi, W. Mori, and C. Clayton
•
Experimental, Theoretical and Computational Studies of
Plasma Based Concepts for Future High Energy Accelerators ..............................98
University of California – Los Angeles, J. Rosenzweig, and C. Pellegrini
•
Theoretical and Experimental Studies in Accelerator Physics .............................105
University of California – San Deigo, N.M. Kroll
•
Theoretical Problems in Accelerator Physics .....................................................110
University of California – San Deigo, S. Schultz
•
Photonic Band Accelerators and Left-Hand Metamaterials .................................115
University of Colorado, J.R. Cary
•
Chaotic Dynamics in Acclerator Physics............................................................118
University of Kansas, J. Shi
•
Develop Nonlinear Corrections Strategies for LHC Interaction Regions ...............123
University of Maryland, A.J. Dragt and R.L. Guckstern
•
Dynamic Systems and Accelerator Theory Group..............................................126
University of Maryland, H. Milchberg and T. Antonsen
•
Accelerator Research Studies- .........................................................................134
University of Maryland, M. Reiser
•
Accelerator Research Studies (Tasks A and B)..................................................141
University of Michigan, D. Umstadter
•
An All-Optical Laser Wakefield Electron Injector ...............................................147
University of New Mexico, J.A. Ellison and T. Sen
•
Investigation of Beam Dynamics Issues at Current and
Future Hadron Colliders..................................................................................151
University of Southern California, T. Katsouleas
•
Theoretical Support Program for Plasma-Based Concepts for Future High
Accelerators...................................................................................................160
University of Wisconsin, Applied Superconductivity Center, L.D.Cooley
•
Understanding Ultimate Limits of Flux Pinning in Superconducting Materials for
Advanced Accelerator Magnets........................................................................165
University of Wisconsin – Applied Superconductivity Center, D.C. Larbalestier
and P.J. Lee
•
High Field Superconductor Development and Understanding: Flux Pinning, High
Field Current Density and Novel Fabrication Processes for Probing the Limits of
Performance in High Field Superconductors .....................................................168
NATIONAL LABORATORY PROGRAMS
Argonne National Laboratory, W. Gai
•
Research Activity Report from the Advance Accelerator R&D.............................172
Brookhaven National Laboratory, I. Ben-Zvi
•
BNL Test Facility ............................................................................................176
Brookhaven National Lboratory, M. Harrison
•
BNL Magnet Program .....................................................................................183
Fermi National Laboratory, G.W. Foster, P.J. Limon and A.V. Zlobin
•
Fermilab Advanced Accelerator Magnet and
Superconductor R&D Programs.......................................................................185
Lawrence Berkeley National Laboratory, J. Corlett
•
Generic R & D of HEP Accelerators ..................................................................190
Berkeley Lab Center for Beam Physics, W. Leemans
•
Optical-Accelerator Experiments at Berkeley Lab ..............................................193
Lawrence Berkeley National Laboratory, S. Gourlay and A. Jackson
•
LBNL Superconducting Magnet Development Program......................................199
Stanford Linear Accelerator Center, R. Siemann
•
Advanced Research and Development Group B ................................................203
GRADUATE STUDENT DATA
•
Appendix A ....................................................................................................204
•
Appendix B ....................................................................................................206
Introduction:
We are pleased to be able to present this book of summary sketches of the work
sponsored by the Advanced Technology R&D Program of the Department of Energy’s
(DOE) Division of High Energy Physics. The work summarized here represents grants
to over 35 universities, industry, and other Federal agencies (NIST and NRL), which we
usually call the “University Program,” as well as directed funds to groups at the National
Laboratories. A very broad spectrum of technologies is covered, ranging from the
metallurgical optimization of superconductors to advanced acceleration techniques,
such as laser and plasma acceleration of particles. Figs. 1 and 2 show the distribution
of these activities by discipline and by funding level. Overall, the Advanced Technology
R&D program is an approximately $24 million effort, with about $13.5 million in the
University Program in fiscal year 2001 and about $10.5 million at the national
laboratories. Additional work in small businesses is supported through the Small
Business Innovation Research (SBIR) grants at an annual level of about $15 million.
The SBIR funding set aside is mandated by law, and the work is described elsewhere.
The criteria for the work that we categorize as “Advanced Technology R&D” is that it is
not related to any specific project or potential project but rather addresses more
fundamental accelerator physics and technology issues for the purpose of advancing
the frontiers in these areas, with a specific focus on topics that may be applicable to
high energy physics. The University Program was first funded in 1982, although a very
limited number of university grants for research in accelerator physics were in place as
early as 1975. It was created on the recommendation of a 1980 HEPAP Subpanel that
the HEP program provide a venue for funding work in accelerator physics and
technology R&D, particularly topics of very high risk but with very high potential payoff
that were unlikely to be supported through our usual national laboratory technology
R&D programs. The present University Program continues to follow this policy. As an
example, it does not support R&D in support of the Next Linear Collider (NLC) or the
muon collider/neutrino source, although there is R&D on these machines at universities
that are funded through other parts of the HEP program. As the Advanced Technology
R&D program has progressed, it became clear that some of the topics could beneficially
be carried out in the HEP supported national laboratories, and so funds separate from
the University Program were found for the laboratories as noted above.
Each of the research summaries was prepared by the principal investigator for that
research and represents that individual’s view of the work performed. The summaries
are snapshots of programs as of September 2001. Later work is obviously not covered.
Included at the end of each summary are lists of the group’s recent talks and papers
published, and a list of current persons working on the research projects supported by
the grant. For those persons wishing to obtain additional information about the
research described, contact information for each principal investigator can be found at
the end of the summary.
Since there has been great interest in the career histories of Ph.D. graduates from the
University Program we have included two appendices with some limited demographic
data. Appendix A lists the current Ph.D. candidate graduate students supported in Fiscal
Year 2001 by the University Program, and Appendix B lists all of the Ph.D. students who
obtained their degrees through the University Program. These are listed by institution;
and we include year of degree, first employment following the degree, and current
employment where known. It should be clearly understood that these lists of Ph.D.
degrees awarded are only a subset of the degrees granted in the U.S. in accelerator
physics and technology. The DOE supported national laboratory programs in Nuclear
Physics, Basic Energy Sciences, as well as High Energy Physics all have research
activities that provide for Ph.D. thesis topics in accelerator physics and technology. In
addition, the National Science Foundation supports work at Cornell, Michigan State and
Indiana University that train Ph.D. students in accelerator physics and technology. As a
very rough guess, we think the total number of Ph.D.’s graduated in accelerator physics
and technology since 1982 approaches 400. We would also like to offer our apologies
for not including data for those persons who have earned Ph.D.’s in the advanced
technology R&D programs at the DOE supported National Laboratories, but the deadline
for completing the book and limited resources prevented our doing so. We hope to
correct this situation in the next edition. There are probably errors and omissions in
these tables. Please contact us with your corrections for the next edition.
We are most grateful to Ms. Melinda Adams of the University of Wisconsin who served
as managing editor of this project. She kept us focused on our task and goals. We
would also like to acknowledge the extensive amount of work put in by Jerry Peters in
assembling, collating and editing the Ph.D. student data. Thanks also to the graphics
and printing department at the Department of Energy for their help on the final
production.
Finally we are very grateful to the senior staff physicist at Fermilab who provided the
impetus to carry out this project.
David F. Sutter
Bruce P. Strauss
Germantown, Maryland
March 2001
Advanced Technology R&D –
~ $23 Million
New Concepts
17%
SC Magnets & Materials
23%
Special Projects
& Topics
18%
Accelerator
School
Accelerator Exp.
Theory and
High Brightness
1%
8%
Code
Sources
13%
4%
Hi Power rf
Sources
16%
HEP – Technology R&D Budget (M$)
– FY 2001
Accel. R&D
Detector R&D
SLAC $0.9
Wash $13.3
SLAC
$21.2
ANL $1.3
BNL $4.6
LLNL $0.5
ANL 0.9
BNL $1.0
LBNL
$2.1
FNAL
$10.4
LBNL $9.2
FNAL $3.5
LANL $0.2
SLAC
$22.1
Wash $13.3
ANL $2.2
BNL $5.6
Total Tech. R&D
LLNL $0.5
LBNL
$11.3
LANL $0.2
FNAL
$13.9
Experimental Research on Microwave Inverse Cerenkov, Inverse FEL, and
Wake Field Accelerators
T.C. Marshall - Columbia University
Summary:
We have received support from DOE for this program for about nine years. In that
time, the program has evolved from a comparatively low energy (0.5-1.0MeV) facility
based at Columbia to a more collaborative program which conducts experiments at a
6MeV beamline at Yale, and at the 40MeV linac facility at ATF/BNL. Currently, we have
the MICA (microwave inverese Cerenkov accelerator) operating at Yale, an ongoing
wake field project at ATF, and for the future, we are participating in the new TW laser
accelerator experiment LACARA, to be run at ATF in 2001-2.
Our first program explored the physics of the IFEL in three experiments, each leading to
the award of a PhD. The original experiment (at Columbia) demonstrated the
acceleration of a trapped electron population using the IFEL mechanism for the first
time. The second experiment (at ATF) used a CO2 laser and is currently in operation as
a prebuncher/accelerator at Brookhaven. The MIFELA (microwave IFEL) experiment
has recently been completed at Yale by Rodney Yoder. It has explored the regime of
IFEL physics where the electrons have large orbital radius: this exposes the electrons to
a radially-variable accelerating field, the same situation as would be encountered in an
IFEL driven by a TW CO2 laser where the wiggler period was several meters and the
electron energy was greater than 10GeV. One should not lose sight of the fact that the
IFEL can make a high gradient accelerator for electrons of up to a few hundred GeV.
The MIFELA experiment demonstrated the trapping and acceleration of the entire
electron bunch.
Recently, we have studied wake field acceleration. In collaboration with Jay Hirshfield’s
group at Yale, we have contributed three new ideas to this subject, which are under
experimental and theoretical study. The first (completed) showed the excitation of
many TM modes by the passage of a short bunch of charge through a cylindrical
dielectric-lined (Alumina) wake field structure. The second is the superimposition of
the wake fields from several very short bunches which can have a total charge equal to
that of one extended large bunch: we find this increases the accelerating gradient.
Third, a wake field “resonator” offers the possibility of accumulating the wake fields of
several passing drive bunches (which can be recirculated), while at the same time
mitigating the transverse bunch instability. The accelerated “test” bunch can be
multiplexed among the “drive” bunches in a staged arrangement of resonators. A
simple experiment will be done at Yale in early 2001 to test the resonator physics.
Dielectric wake field accelerators require neither lasers nor new rf sources.
Figure 1. The cylindrical wake field resonator, showing a train of bunches passing
through an annular dielectric liner.
Some recent results:
•
Wake field experiment at ATF: [7] In 1999 we ran a single-bunch wake field
experiment at ATF. The bunch charge provided by the ATF rf photocathode gun
and linac was 0.2nC, energy = 40MeV, and bunch length = 10psec. The
apparatus, consisting of an alumina annular liner with an axial 3mm dia hole,
was installed in the ATF beamline; microwave signals from the TM modes set up
in the apparatus were picked up by a radial wire probe and conveyed to a
detector and a spectrum analyzer. Altogether, six modes between 1.7 and
17GHz were found, limited only by the capability of the spectrum analyzer.
Comparing the measured and computed mode frequencies determines the
dielectric constant 9.65, which is quite close to the value obtained from an
independent measurement. This experiment shows a short bunch will excite
many modes. From these measurements, we have found the correct
dimensions for the dielectric liner which will give a suitable wake field period
matched to the bunch spacing available at ATF; this will permit a study of
multiple bunches to be made in 2001. Data (from others) shows that alumina
has no dispersion up to 200GHz.
•
The wake field resonator: [8] A wake field resonator has been studied using
the PIC code KARAT. The parameters of the resonator are chosen such that the
period of the wake fields is the same as the spacing of the drive bunches, which
is also the length of the resonator. (Fig. 1) Then the wake field of a passing
charge bunch will travel down the resonator and back so as to arrive at the front
reflector just as the next bunch enters, (a type of mode-locking). In Figs. 2 and
3 we show the result of superimposing the fields of 7 bunches in the resonator
by this means (L=10.5cm); the wake fields remain well synchronized, and the
amplitude of the resulting wake field builds up linearly with each additional
bunch. Because the drive bunches have lower energy than the test bunches, the
former can be deflected from the system, re-energized, and recirculated. Also,
since transverse deflection is approximately quadratic in time, the transverse
instability for a shorter module with higher fields is more tolerable than for a
long module with proportionately weaker fields. We are now constructing a
resonator module for testing an injected drive bunch train on the Yale 6MeV
beamline in 2001.
Figure 2. The accumulated accelerating wake field amplitude Ez in the resonator set
up from the passage of 7 identical “drive” bunches. ↓
12
WAKE FIELD
10
8
6
4
2
0
2
4
6
8
BUNCH #
Figure 3. The composite wake field Ez at 2.55nsec set up by seven drive bunches in
the resonator; bunch #8 has just entered at the left. Note the Cerenkov wake in
the dielectric. The bunches enter on-axis from the left and exit on the right, while
the waves reflect in the resonator (length = 10.5cm = bunch spacing). The vacuum
hole has radius = 1.5mm, and the dielectric fills the region out to the radius 1.05cm.
Publications:
1. T.C. Marshall and T.B. Zhang, “A Survey of Microwave Inverse FEL and Inverse
Cerenkov Accelerators”, in “New Modes of Particle Acceleration -- Techniques and
Sources”, p. 105, AIP Conference Proceedings #396, Z. Parsa, editor (1997)
2. T.-B. Zhang, J.L. Hirshfield, T.C. Marshall, and B. Hafezi, “Stimulated Dielectric
Wakefield Accelerator”, Physical Review E56 , 4647 (1997)
3.T.B. Zhang, T.C. Marshall et al, “Microwave Inverse Cerenkov Accelerator”,
Physical Review E54, 1919 [1996]
4. T-B. Zhang, T.C. Marshall, and J.L. Hirshfield, “A Cerenkov Source of High Power
Picosecond Microwaves”, IEEE Trans. Plasma Science 26, 787 (1998)
5. T.C. Marshall, T-B. Zhang, and J.L. Hirshfield, “The Stimulated Dielectric WakeField Accelerator: A Novel RF Structure”, [Invited paper] Advanced Accelerator
Concepts Workshop, in AIP Conference Proceedings #472, p. 27, (1999), Wes
Lawson editor
6. T-B. Zhang, J.L. Hirshfield, T.C. Marshall, and B. Hafizi, “Stimulated Dielectric
Wakefield Accelerator”, 1, p. 666, Proceeding of the 1997 Particle Accelerator
Conference, Volume 1. Editors: Comyn, Craddock, Reiser, and Thomson (IEEE and
APS, publ.1998)
7. J-M. Fang, T.C. Marshall, et al, “An Experimental Test of the Theory of the
Stimulated Wakefield Accelerator”, Proceedings of the 1999 Particle Accelerator
Conference, Vol. 5, p. 3627. IEEE catalog number 99CH36366, A. Luccio and W.
MacKay (1999)
8. T.C. Marshall, J-M. Fang, et al., “Multi-Mode, Multi-Bunch Dielectric Wake Field
Resonator Accelerator”, Advanced Accelerator Concepts Workshop, AIP Conference
ProceedingsSanta Fe, NM (June, 2000)
9. R.B. Yoder, T.C. Marshall, and J.L. Hirshfield, “Acceleration Results from the
Microwave Inverse FEL Experiment”, Advanced Accelerator Concepts Workshop, AIP
Conference Proceedings, Santa Fe, NM (June, 2000); submitted to Physical Review
Current Staff: (As of 9/1/00)
•
•
•
Dr. J-M. Fang Mr. Sergey Shchelkunov Professor T.C. Marshall -
Postdoctoral Research Scientist
Graduate Student Research Assistant
Principal Investigator
Accelerator Simulation Code Development
Summary:
R. Talman – Cornell University
Though the accelerator community has profited enormously from the revolutionary
advances in computers and computer software, the sharing of special purpose
accelerator codes has been painfully slow. Ideally all of the following would be true,
•
The same codes should be applicable to different accelerators.
•
Different codes should be applicable to the same accelerator (to test agreement of
capabilities they both have.)
•
The same code used for the design and analysis of the accelerator should be built
into the control system of the accelerator. This is “model-based” control.
•
Special-purpose codes should be modular in ways that permit them to be combined
as parts of more general calculations.
To achieve these goals has been the guiding principle of work under this grant.
ACCOMPLISHMENTS TO DATE
Many of the goals just mentioned have been realized in the form of the UAL (Unified
Accelerator Libraries) which is the primary product of our DOE grant. The evolution of
this accelerator simulation software is indicated in the figure on the next page. This
section describes verbally the chronology that the figure illustrates. Since the names of
the leading contributors are given in the figure, they will not be repeated here.
Furthermore the names of many of the significant contributors, over the last three
years, can be inferred from the publication list that follows. The lion's share of the work
has been done under DOE auspices, much, but far from all, under the current grant. I
have been a collaborator in the majority of the work to be described.
As the SSC was being planned, it was realized that a design as conservative as the
Fermilab Tevatron might be unacceptably expensive. At the CDG (Central Design
Group) plans were set in motion to study this issue experimentally (Experiment E778)
and by computer simulation and other theoretical studies. The program TEAPOT (Thin
Element Program for Optics and Tracking) was developed both to design and analyze
experiment E778 and to anticipate performance of the SSC using computer simulation.
At the same time, and the same place, mapping techniques and differential algebra
(DA) were being developed to put the numerical work on a firmer and more powerful
theoretical foundation. At the SSC project in Dallas a computational structure called PAC
(Platform for Accelerator Computations) was developed, with the purpose of permitting
the integration of diverse computer codes. PAC adopted the "object oriented" approach
to computer software, whose value was just becoming universally appreciated at the
time. At Cornell, in the period following the termination of the SSC, this architecture
was exploited to integrate TEAPOT++ (upgraded from procedural Fortran to object
oriented C++) along with PAC and DA into UAL (Unified Accelerator Libraries.) For the
first time, this permitted element-by-element tracking to be integrated with analyses
using maps of arbitrary order. This satisfied the goal “Special-purpose codes should be
modular in ways that permit them to be combined as parts of more general
calculations.” The next code to be integrated seamlessly into this environment was MAD
(Methodical Accelerator Design) which is the pre-eminent lattice code for designing
transfer lines and sectors of high energy lattices. Shortly thereafter, responsive to the
"Call for a New Accelerator Standard" listed in the references, and driven by the need,
within the US-LHC collaboration, for a mechanism to share design information of the
LHC, a Standard Exchange Format (SXF) was developed and integrated into UAL, (as
well, of course, as into CERN database programs). Design issues for the VLHC (Very
Large Hadron Collider) have also been addressed.
Subsequent work has concentrated on applying this computational environment to
practical accelerators. Much of what has been done can be inferred from the titles of
the attached publication list. The greatest difficulties are of a mundane nature; they
amount to interfacing between UAL and heterogeneous “proprietary” codes by placing
“wrappers” around the programs and data files that have developed over the years of
operation of accelerators like FNAL and CESR. It was more straightforward to apply UAL
to RHIC (Relativistic Heavy Ion Source), because of its more recent vintage, and UAL
played a significant role in the design of RHIC. The much acclaimed, model-based,
control of RHlC derives, to a considerable extent, from algorithms and experience with
UAL simulation. This has met, at least partially, another goal “The same code used for
the design and analysis of the accelerator should be built into the control system of the
accelerator.” It is expected that this goal will be fully met with the SNS (Spallation
Neutron Source). This work is proceeding at the SNS project under the direction of
Malitsky, who went from Cornell to SNS in 1999. So far this has included the capability
of importing special purpose codes ACCSIM, SIMPSONS, and SAMBA into the UAL
environment. This adds capabilities such as space charge analysis, radiation damage,
and injection "painting" into the simulation environment. Also progress has been made
towards integrating UAL into the SNS control system.
Publications:
1. F. Pilat, C. Trahern, J. Wei, T. Satogata, and S. Tepikian, “Modeling RHIC Using the
Standard Machine Format Accelerator Description,” PAC97, 1997.
2. N. Malitsky and R. Talman, “Study of LHC Aperture Dependence on Tune Separation,
Using Thin Lenses, Phase Trombones, and ‘Unified Accelerator Libraries,’” CERN LHC
Project Report 130, Feb., 1998.
3. C. Iselin, E. Keil and R. Talman, “Call For a New Accelerator Description Standard,”
Beam Dynamics Newsletter 16, April, 1998.
4. N. Malitsky and R. Talman, “The Framework of Unified Accelerator Libraries,”
ICAP98, Monterey, 1998.
5. H. Grote, J. Holt, N. Malitsky, F. Pilat, R. Talman, C. Trahern, “SXF: Definition,
Syntax, Examples,” RRIC/AP/155 (1998).
6. N. Malitsky and R. Talman, “Accelerator Description Exchange Format,” ICAP98,
Monterey, 1998.
7. M. Malitsky and T. Pelaia, “Integration of Unified Accelerator Libraries with CESR,”
CBN, 98-9, 1998.
8. N. Malitsky, J. Smith, J. Wei, and R. Talman, “UAL-Based Simulation Environment for
Spallation Neutron Source Ring,” p. 2713, Proc. 1999 PAC, New York.
9. Application of SXF Lattice Description and the UAL Software Environment, to the
Analysis of the LHC, 1999 Particle accelerator Conference, New York, p. 2716.
10. R. Talman, W. Fischer, F. Pilat, and V. Pitsin, “Optimizing VLHC Single Particle
Performance,” Nuclear Instruments and Methods, submitted for publication, 2000.
Current Staff:
•
Prof. Richard Talman
Contact Information:
Professor Richard M. Talman (PI)
Cornell University
216 Newman Laboratory
Ithaca, NY 14853-2801
PHONE: 607-255-5017
FAX: 607-254-4552
EMAIL: [email protected]
WEBSITE: http://Inssunl.hepth.cornell.edu/-ual/
Figure 1. Lineage of the TEAPOT family.
Electron Beam Transport in Advanced Plasma Wave Accelerators
R. L. Williams, Florida A. & M. University
Compact particle accelerators of the future may well make use of the very large
electrostatic fields and accelerating gradients that are found in plasma waves, which are
density waves in an ionized gas. These plasma waves are attractive for accelerating
particles because they move with speeds very close to the speed of light, and because
they have very large electrostatic fields, typically on the order of gigavolts per meter.
The acceleration of electrons to high energies over short distances by plasma waves
has been demonstrated in several laboratories, however one of the present challenges
is to extend the acceleration length so that much higher energies can be achieved.
Knowledge of the amplitude of these plasma waves is very important for researchers
and eventually for operating plasma wave accelerator systems. Measurement of the
amplitude of such extreme electrostatic plasma wave fields must be done indirectly, and
we are involved in discovering, understanding and developing new ways to detect and
measure such large electric fields.
One common method of detection is to scatter a laser beam off the wave and to
deduce the wave amplitude by measuring the deflection and frequency shift of the laser
light. We will use this method as a calibration baseline. But we are experimenting with
a separate way to measure the large electrostatic fields, based on injecting and
transporting a low energy (5 to 50 keV) electron beam transversely across the wave,
and observing the resulting distortion of the beam cross section. Essentially, a circular
beam entering the plasma wave transversely (figure 1.a) would have a highly distorted
cross section upon exiting the beam (figure 1.b), as measured on a fluorescing screen,
similar to a tv screen. Our computer simulations predict that the amount of cross
section distortion in one direction is linearly proportional to the longitudinal electrostatic
field that would be used to accelerate particles to very high energies over very short
distances (figure 2). The distortion of the cross section in the perpendicular direction is
proportional to the radial plasma wave electric fields that focus and defocus the
accelerating beam (figure 2).
In our laboratory we have used CO2 and YAG lasers to create the plasma in
which the plasma waves will be generated; transported the electron beam through the
plasma and measured its cross section on a fluorescing screen; devised methods for
controlling and shortening the laser pulse using a plasma shutter; and developed a
spectroscopic technique for measuring the density and temperature of the preionized
plasma created by the electron beam. A fortunate consequence of using the electron
beam as a diagnostic is that it creates a low density plasma along its trajectory, and we
are presently investigating this preionization plasma to see if it will enhance the process
of making plasma and plasma waves by the lasers. We are continuing to make
progress in the laboratory and, in the near future, will make plasma waves and start
studying them using the traditional laser scattering techniques as well as our new
electron beam technique.
Figure 1. Computer generated cross sections of the electron beam (a) before entering
the plasma wave and (b) after exiting the plasma wave that has a 20% plasma wave
amplitude, aw. The distortion in the z direction is due to the longitudinal accelerating
field and the distortion in the x direction is due to the radial focusing/defocusing field.
Figure 2. Summary of cross section (spot width) versus plasma wave amplitude, aw, for
the longitudinal electrostatic fields (squares) and radial electrostatic fields (circles).
Current Staff:
Prof. Ronald L. Williams
Kurtrease Lafate
Graduate Student
Prof. Ronald L. Williams
Department of Physics
Jones Hall, Room 205
Florida A. & M. University
Tallahassee, Florida 32310
Phone: (850) 599-8383
FAX: (850) 599-3968
E-Mail: (main): [email protected]
E-Mail: (alternate#1): [email protected]
E-Mail: (alternate#2): [email protected]
Liquid Helium Fluid Dynamics Studies
Steven W. Van Sciver- Florida State University
Summary:
The R&D program has two main purposes. The first is to develop a broader
understanding of liquid helium as a technical fluid so that it can be better applied in
large accelerator systems. The second is to educate professionals who will contribute
to future accelerator development worldwide. The R&D is primarily an experimental
effort with emphasis on heat transfer and fluid dynamics studies of all phases of liquid
and vapor (and two phase) helium. In recent years, the majority of our work has
focused on the engineering aspects of superfluid helium (He II) as it is being applied in
several projects currently under development (e.g. Large Hadron Collider). For one
activity, we have completed a project to measure and model heat and mass transfer in
horizontal stratified two phase He II/vapor. We measured heat transfer and pressure
drop in a model test section as it depends on void fraction, temperature and flow rate
[Refs. 1, 9, 12, 14, 16]. We also developed analytical and numerical models to describe
the observed phenomena [Refs. 11, 15]. This work has been done partially in
collaboration with DESY, Hamburg under the TESLA program. We are sharing with
DESY the services of a postdoc, who is conducting the numerical analysis and assisting
with experiments.
Over the last two years, we have focused our research effort on understanding the
properties of single phase He II at the extremes of heat and mass transfer. Two
experiments are underway.
One involves the study of intense thermal shock in He II where the heat is transported
by a process known as second sound at a velocity of about 20 m/s. This mechanism
has the potential of providing an added stabilizing effect to high current density
magnets with porous windings containing He II. In these experiments, we have
recently observed He II thermal shock [Ref. 10] and are now modifying the apparatus
to be able to study the fundamental nature of the turbulence mechanisms that limit this
process. This work is the Ph.D. thesis topic for the physics graduate student supported
under our program.
The other experimental effort, supported under this program, involves fluid dynamics
and heat transport in He II at extremely high flow velocities (Reynolds numbers, uD/µ).
The main experiment is a measurement of the pressure drop and heat transport in He
II flowing in a tube at velocities approaching 20 m/s (ReD ≈ 107). We have recently
demonstrated that He II, even at these high velocities, follows a classical friction factor
correlation, a result which has surprised the physics community involved in He II
research [Ref. 17]. This project represents the thesis work of the second Ph.D.
engineering student supported by our program. In a side project similarly designed to
test the high Reynolds number behavior of He II, we have performed a drag coefficient
measurement on a sphere in flowing He II [Refs. 4, 7]. This measurement, which is
probably the most classic of all fluid dynamics experiments, also displays normal fluid
behavior including the well known “drag crisis” at ReD ≈ 105.
Publications:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
S.W. Van Sciver, X. Huang and J. Panek, “Heat and Mass Transfer Processes in
Connected Saturated He II Baths,” Cryogenics 37, 745 (1997)
G. Horlitz, et al (S.W. Van Sciver), “The TESLA 500 Cryogenic System and He II
Two-Phase Flow: Issues and Experiments,” Cryogenics 37, 719 (1997)
J. Panek, Y. Xiao and S.W. Van Sciver, “Liquid Level Control using a Porous Plug
in a Two Phase He II System,” Advances in Cryogenic Engineering Vol. 43, 1401
(1998)
M.R. Smith and S.W. Van Sciver, “Measurement of the Pressure Distribution and
Drag on a Sphere in Flowing He I and He II,” Advances in Cryogenic Engineering
Vol. 43, 1473 (1998)
S.W. Van Sciver, “Forced Flow He II Cooling for Superconducting Magnets Design Considerations,” Cryogenics 38, 503 (1998)
B. Baudouy, M. Takeda and S.W. Van Sciver, “Hydraulic Characteristics of
Centrifugal Pumps in He I near Saturation Conditions”, Cryogenics 38. 737
(1998)
M.R. Smith, D.K. Hilton and S.W. Van Sciver, “Observed Drag Crisis on a Sphere
in Flowing He I and He II,” Physics of Fluids Vol. 11, 1 (1999)
D. K. Hilton, J. S. Panek, M. R. Smith and S. W. Van Sciver, “ A Capacitive Liquid
Helium Level Sensor Instrument” Cryogenics 39, 485 (1999)
J. S. Panek and S. W. Van Sciver, “Heat Transfer in a Horizontal Channel
Containing Two-Phase He II,” Cryogenics 39, 627 (1999)
D. K. Hilton, M. R. Smith and S. W. Van Sciver, “Thin-Film Thermometer and
Heater Design for the Detection and Generation of Second Sound Pulses,”
Advances in Cryogenic Engineering, Vol. 45 (2000)
Y. Xiang, N. N. Filina, S. W. Van Sciver, J. G. Weisend II and S. Wolff, “Numerical
Study of Two-Phase He II Stratified Channel Flow,” Advances in Cryogenic
Engineering, Vol. 45 (2000)
S. W. Van Sciver, J. S. Panek and D. Celik, “Flow in Horizontal Two Phase He
II/Vapor,” Advances in Cryogenic Engineering, Vol. 45 (2000)
M. R. Smith, T. Zhang,..(S. W. Van Sciver), “Experimental Investigation of the
Thermal Resistance in Niobium Samples for Superconducting RF Cavities”,
Advances in Cryogenic Engineering, Vol. 45 (2000).
S. W. Van Sciver, “Heat and Mass Transfer Processes in Two Phase He II/Vapor,”
Cryogenics 39, 1039 (1999).
Y. Xiang, B. Peterson, S. Wolff, S. W. Van Sciver , and J. G. Weisend II,
“Numerical Study of Two-Phase Helium II Stratified Channel Flow with
Inclination,” IEEE Transactions On Applied Superconductivity 10, 1530 (2000)
16.
17.
S. W. Van Sciver, D. Celik and J. S. Panek, “Heat and Mass Transfer in Two
Phase He II,” 12th Intersociety Cryogenics Symposium, AIChE Spring Meeting,
Atlanta, GA, March 5-9, 2000.
M. R. Smith, B. Baudouy, S. Fuzier and S. W. Van Sciver, “High Reynolds Number
He II Fluid Dynamics,” 12th Intersociety Cryogenics Symposium, AIChE Spring
Meeting, Atlanta, GA, March 5-9, 2000.
Current Staff:
•
•
•
•
•
Steven W. Van Sciver
Dogan Celik
Xiang Yu
David Hilton
Silvie Fuzier
Principal Ivestigator
Postdoc
Postdoc (DESY, but spends 50% time with our group)
Graduate Student (physics)
Graduate Student (ME)
Steven W. Van Sciver (PI)
Florida State University
National High Magnetic Field Laboratory
1800 E. Paul Dirac Drive
Tallahassee, Florida 32306
PHONE: 904/6447-0998
E-MAIL: [email protected]
Beam Dynamics and Beam Manipulations
S.Y. Lee
Indiana University
Summary:
The Accelerator Physics group at Indiana University is composed of 1 faculty, 1 postdoc,
who has recently moved to Oak Ridge National Laboratory in Tennessee, and 7
graduate students. Our research areas include: (1) nonlinear beam dynamics research,
(2) physics of beam cooling, (3) beam manipulation methods, (4) collective beam
instabilities, and (5) spin dynamics.
In past few years, our major findings can be listed as follows:
(1) Measure and model nonlinear Hamiltonian for particle motion in an accelerator.
(2) Derive a condition for the variable momentum compaction lattice.
(3) Discover the driving mechanism of odd-order and even order snake resonances,
uncover and test methods for spin preservation in polarized beam acceleration.
(4) Explore beam dynamics for quasi-isochronous storage rings, discover the beam
stability condition for QI dynamical systems, and analyze effects of noise on
particle motion in QI storage rings.
(5) Derived the minimum emittance condition for three and multiple bend
achromats, design example lattices, e.g. minimum emittance 5-bend achromats,
etc.
(6) Derived the envelop equation for space charge dominated beams in
synchrotrons, obtain the condition of global chaos for space charge dominated
beams, identify particle-envelope, envelope structure, and particle structure
resonances and their contribution to halo formation.
(7) Perform systematic experiments on bunch compression, and derive condition for
a possible storage ring based high gain FEL.
(8) Measured the electron-cooling force at the IUCF Cooler, and studied the effect of
magnetized cooling on beam dynamics, observed the Hopf bifurcation, and
employing the effect to measure the beam temperature.
(9) Carry out systematic experiments on space charge effect during the bunch
compression stage in a booster synchrotron.
In past two years, we have carry out experiments at the AGS/RHIC for the polarized
beam acceleration experiments, and space charge experiments at the Cooler Injector
Synchrotron (CIS). The AGS/RHIC polarized beam experiments have been used to test
the feasibility of overcoming snake resonances in RHIC.
We are also actively working on the CIS space charge experiments are intended to
simulate the injection process of the SNS ring compressor. The CIS injection energy is 7
MeV. The injection process is to compress a 200 microsecond H- beam pulse into a 100
ns beam bunch in the CIS. We can measure the emittance of the compressed beam as
a function of injection turn number in the extraction transfer line. We have carried out
two successful experiments in the past year. More experiments with a high current
source are planned in the near future. Future studies include space charge
compensation experiments in collaboration with Fermilab physicists.
We continue to study the feasibility of electron injection into the Cooler (3.6 Tm
momentum rigidity). With an electron injector, we can examine physics of low energy
electron storage rings, feasibility experiments on optical stochastic cooling, and the
feasibility study of electron cooling for high energy storage rings. At the maximum
energy of 1 GeV, the electron storage ring can provide soft X-ray for science research,
and medical applications.
Publications:
1. S.Y. Lee, Accelerator Physics (World Scientific, Singapore, 1999)
2. C.M. Chu, et al., “Diffusion Mechanism with rf phase modulation,” Phys Rev.
E~60, 6051 (1999)
3. M. Bai, et al., “Observation of the hybrid spin resonance,” Phys. Rev. Lett. 84,
1184 (2000)
4. K.M. Fung, et al., “Bunch Compression manipulations,” Phys. Rev. Special Topics:
Accelerators and Beams, 3, 100101 (2000).
5. K.Y. Ng, S.Y. Lee, “Unified Treatment of Collective Instabilities and Nonlinear
Beam Dynamics,” Proceedings of Particle Accelerator Conference (1999, New
York)
6. M. Ball, et al., “Diffusion mechanism of particle beams in the presence of phase
modulation in double rf systems,” Proceedings of Particle Accelerator Conference
(1999, New York)
7. M. Ball, et al., “Beam Motions Near Separatrix,” Proceedings of Particle
Accelerator Conference (1999, New York)
8.
K.M. Fung, et al., “Space charge effect on betatron oscillations,” Proceedings of
Particle Accelerator Conference (1999, New York)
Current Staff:
•
•
•
•
•
•
•
•
•
Lee, S.Y.
Chu, C.M. Paul
Fung, K.A.
Cousineau, Sarah
Ranjbar, Vahid
Zhang, Yuankai
Guo, Weiming
Wang, Shaoheng
Al-Harbi, Nader
PI
Postdoc (Now at Oak Ridge National Laboratory)
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Graduate Student
S.Y. Lee (PI)
Indiana University
2401 Milo B. Sampson Lane
Bloomington, IN 47408
PHONE:
FAX:
E-MAIL:
Website:
812/855-2899 or 812/855-7637
812/855-6645 or 812/855-3355
[email protected]
http://www.indiana.edu/~uspas/iuap/ap.html
Montage
Figure 1: Preliminary rms emittance measured from the CIS beam as a function of
beam current, expressed in the number of turns.
Figure 2: Data (crosses) of maximum compression ratio from a bunch compression
experiment are compared with theory (line) and multiparticle simulations (other
symbols) with different rms cut in the calculation of the rms values.
Periodically Focused Intense Charged-Particle Beams
Chiping Chen
Intense Beam Theoretical Research Group
Plasma Science and Fusion Center
Massachusetts Institute of Technology
Summary:
Under the auspices of this grant, we conduct vigorous theoretical and numerical
investigations of periodically focused intense charged-particle beams in parameter
regimes relevant to the development of advanced high-current, high-power accelerators
for high-energy and nuclear physics research and applications, as well as in parameter
regimes relevant to the development of high-power microwave and millimeter-wave
sources that are considered as drivers for the Next Linear Collider (NLC).
The recent major contributions made in our research are:
•
•
•
•
•
Identification of electron beam halo formation as an important mechanism for the
electron beam loss observed in the SLAC 11.4 GHz, 50 MW Periodic Permanent
Magnet (PPM) Focusing Klystron Amplifier;
Discovery of a scaling law for the confinement of a highly bunched beam;
Discovery of corkscrewing elliptic beam equilibrium for ultrahigh-brightness
propagation in a linear focusing channel consisting of an arbitrary combination of
solenoidal and quadrupole magnets with field tapering;
Determination of nonlinear resonant and chaotic structures in well-matched
periodically focused beams;
Application of Green’s function techniques in the 2-D and 3-D modeling of spacecharge effects in high-brightness, space-charge-dominated beams.
Results of our research were featured in invited papers presented at the 1998
International Linear Accelerator Conference in Chicago and the 1999 APS Division of
Plasma Physics Annual Meeting in Seattle.
1997-2000 Publications in Referred Journals
1. “Mechanisms and Control of Beam Halo Formation in Intense Microwave Source
Accelerators,” (Invited Paper) C. Chen and R. Pakter, Phys. Plasmas 7, 2203(2000).
2. “Cold-Fluid Equilibrium for a Corkscrewing Elliptic Beam in a Variably Focusing
Channel,” R. Pakter and C. Chen, Phys. Rev. E62, 2789 (2000).
3. “Electron Beam Halo Formation in High-Power Periodic Permanent Magnet Focusing
Klystron Amplifiers,” R. Pakter and C. Chen, IEEE Trans. Plasma Sci., Vol. 28, No. 3,
June (2000).
4. “Confinement Criterion for a Highly Bunched Beam,” M. Hess and C. Chen, Phys.
Plasmas 7, in press (2000).
5. “Phase Space Structure for Intense Charged-Particle Beams in Periodic Focusing
Transport Systems,” C. Chen, R. Pakter, and R. C. Davidson, Phys. Plasmas 6, 3647
(1999).
6. “Kinetic Description of High-Intensity Beam Propagation through a Periodic Focusing
Field Based on the Nonlinear Vlasov-Maxwell Equations,” R. C. Davidson and C.
Chen, Part. Accel. 59, 175 (1998).
7. “Rigid-Rotor Vlasov Equilibrium for an Intense Charged-Particle Beam Propagating
through a Periodic Solenoidal Magnetic Field,” C. Chen, R. Pakter, and R. C.
Davidson, Phys. Rev. Lett. 79, 225 (1997).
8. “Halo Formation and Chaos in RMS Matched Beam Propagation through a Periodic
Solenoidal Focusing Channel,” Y. Fink, C. Chen, and W. P. Marable, Phys. Rev. E55,
7557 (1997).
Selected 1998-2000 Publications in Conference Proceedings
1. “Confinement of Bunched Beams,” M. Hess and C. Chen, Proceedings of 2000
Advanced Accelerator Concept Workshop, in press (2000).
2. “Electron Beam Halo Formation in Periodic Permanent Magnet Focusing Klystron
Amplifiers,” C. Chen, M. Hess, and R. Pakter, Intense Microwave Pulses VII, edited
by H. E. Brandt, SPIE Proc. 4031, in press (2000).
3. “Space Charge Effects in Rectilinear Motion: Emittance Compensation, Pulse
Shortening, and Halo Formation - Working Group Summary,” C. Chen and M.
Ferrario, Proceedings in the Second ICFA Advanced Accelerator Concept Workshop
on the Physics of High-Brightness Beams, edited J. Rosenzweig and L. Sarafini, in
press (World Scientific, 2000).
4. “Green’s function description of space charge in intense charged-particle beams,” M.
Hess, C. Chen, and R. Pakter, Proceedings of 1999 Particle Accelerator Conference
(1999), p. 2752.
5. “Halo formation in intense linacs," (Invited Paper) C. Chen, Proceedings of 19th
International Linac Conference (Argonne National Laboratory Report ANL-98/28,
1998), p 729.
2
Selected Research Highlights
HALO AND CORE RADII (cm)
Identification of Halo Formation as a Mechanism for Beam Loss Observed in
SLAC 11.4 GHz, 50 MW PPM (50XP) Klystron*
(*Invited Paper Presented at 1999 APS DPP Meeting)
0.8
halo radius
core radius
0.6
0.4
0.2
0.0
0.0
20.0
40.0
60.0
AXIAL DISTANCE (cm)
80.0
Plot of the halo radius (solid curve) and core radius (dashed curve) as a function of the
axial distance obtained from the PFB2D simulation of electron beam dynamics in the
SLAC 50XP klystron amplifier. The electron beam halo reaches the beam tunnel with a
radius of 0.47625 cm at the rf output section (i.e., at an axial distance of 42 cm),
resulting in beam loss observed.
Confinement Criterion for a Bunched Beam
1.5
2-D
2ωp2/ωc2
1.0
0.5
3-D
0.0
0.0
1.0
2.0
3.0
α=2πa/L
4.0
5.0
6.0
Plot of the highest value of the effective self-field parameter 2ωp2/ωc2 as a function of
α=2πa/L for radial confinement of unbunched (2D) and highly bunched (3D) beams in
the beam frame. Here, ωp is the effective plasma frequency, ωc is the cyclotron
frequency, a is the waveguide radius, and L is the spacing between charged-particle
bunches.
3
Current Research Staff
•
•
•
•
•
Chiping Chen
John A. Davies
William Guss
Renato Pakter*
Michael Shapiro
Research Staff
Research Staff
Research Staff
Research Staff
Graduate Students
• Mark Hess
• Garrett Otto
• Vadim Roytershteyn
• Evgenya Smirnova
Undergraduate Researcher
• Edem Tsikata
*Now on the faculty of Instituto de Fisica, Universidade Federal do Rio Grande do Sul,
Brazil in beam physics research and education.
Dr. Chiping Chen (PI)
77 Massachusetts Avenue NW16-176
Cambridge, Massachusetts 02139
PHONE: 617/253-8506
4
17 GHz High Gradient Accelerator Research
Summary:
Richard Temkin, MIT
The MIT Plasma Science and Fusion Center conducts research on a 17.1 GHz RF
photocathode gun and high gradient electron accelerator.
The RF gun is powered by a 25 MW, 17.1 GHz klystron built by Haimson Research Corp.
and installed at the MIT modulator / electron gun facility. A picosecond Ti: sapphire
laser pulse, tripled to 267 nm wavelength, is injected into the RF gun at a fixed phase
relative to the klystron. The RF gun produces 1 ps electron bunches of up to 0.1 nC
with energy in excess of 1 MeV and emittance of about 3 π mm mrad with accelerating
gradients in excess of 200 MeV/m.
The Haimson 17 GHz, 0.5 m long accelerator has been installed at MIT and has
achieved first operation with electron bunches of 17 MeV. This is the highest frequency,
stand-alone accelerator in the world. The design parameters of this accelerator are:
input beam energy of 0.5 MeV from a DC electron gun; output beam energy of 20 to 30
MeV; 0.25 A average current; 80 A peak current; bunch length of 1.1 degrees (180 fs);
energy spread of < 1.1%; 1×108 electrons per bunch; macropulse width of 1 µs; bunch
separation of 59 ps and 1.7×104 micropulses per macropulse. The accelerator and
klystron are driven by the MIT high voltage modulator that produces flat top pulses at
up to 700 kV for 1 µs at a repetition rate of 4 Hz. The quasi-constant accelerating
structure consists of 94 cavities in a 2π/3 mode. The Haimson accelerator currently
utilizes a DC gun with beam formation using a chopper and a prebuncher. However, the
0.5 m accelerator can also accept the beam from an RF gun at a beam energy of 2
MeV.
In the next phase of this research program, we will investigate the operating
characteristics of the accelerator, integrate the RF gun with the accelerator as an
injector and develop diagnostics of the accelerator performance. We intend to measure
the emittance and the bunch length of the electron beam from the accelerator. We will
also conduct research on novel accelerator structures including photonic bandgap
structures and quasi-optical or overmoded structures. Theoretical research will support
the experimental research program. The proposed research is carried out primarily by
graduate students and postdoctoral associates thus assuring that educational goals are
heavily emphasized.
Publications:
1. W.J. Brown, S. Trotz, K.E. Kreischer, M. Pedrozzi, M.A. Shapiro, and R.J. Temkin,
“Experimental and Theoretical Investigations of a 17 GHz RF Gun”, Nuclear
Instruments and Methods in Physics Research A, 1999, Vol. 425, No. 3, pp. 441-459.
2. Haimson J., Mecklenburg B., Stowell G. A field symmetrized dual feed 2 MeV RF gun
for a 17 GHz electron linear accelerator. AIP. American Institute of Physics
Conference Proceedings, AAC1998, no.472, 1999, pp.653-67.
3. Haimson J, Mecklenburg B, Stowell G, Kreischer KE, Mastovsky I. Preliminary
performance of the MKII 17 GHz traveling wave relativistic klystron. AIP. American
Institute of Physics Conference Proceedings, Pajaro Dunes, no.474, 1999, pp.137.
4. Hess M., R. Pakter, and C. Chen, 1999, “Green’s function description of space
charge in intense charged-particle beams,” Proceedings of the 1999 Particle
Accelerator Conference.
5. Hess M., C. Chen, 2000, Phys. Plasmas, in press.
6. L. C.-L. Lin, S. C. Chen and J. S. Wurtele, “On the Frequency Scaling of RF Guns,” in
AIP Conf. Proc. 335, Paul Schoessow, editor, AIP Press, New York, pp. 704-707
(1995).
7. L.C.-L. Lin, S. C. Chen, J. S. Wurtele, “An Equivalent Network Analysis of Waveguide
Broad-Wall Coupled RF Gun Structures, “Nucl. Instr. & Meth. Phys. Res., Section A,
Vol. 384, no.2-3, pp. 274-284 (1997).
8. W. L. Menninger, B. G. Danly, S. Alberti, S. C. Chen, E. Giguet, J. L. Rullier, and R. J.
Temkin,”CARM and harmonic gyro-amplifier experiments at 17 GHz,” Proceedings of
the 1993 Particle Accelerator Conference, IEEE Cat. No.93CH3279-7), IEEE Press,
pp. 2656-8 (1993).
9. W. L. Menninger, B. G. Danly, R. J. Temkin, “Multimegawatt relativistic harmonic
gyrotron traveling-wave tube amplifier experiments, IEEE Transactions on Plasma
Science, Vol.24, No.3 pp. 687-99 (June, 1996).
10. W. J. Mulligan, S. C. Chen, G. Bekefi, B. G. Danly, and R. J. Temkin, “A High-Voltage
Modulator for High-Power RF Research,” IEEE Trans. Electron Dev. Vol. 38, pp. 817821 (1991).
11. M.A. Shapiro, W.J. Brown, and R.J. Temkin, “Photonic Bandgap Structure Based
Accelerating cell,” Proc. 1999 Particle Accelerator Conf. (IEEE, 1999), Vol.2, pp. 833835.
12. M.A. Shapiro and R.J. Temkin, “High Power Miter-Bend for the Next Linear Collider,”
Proceeding of the 1999 Particle Accelerator Conference, IEEE, 1999, Vol. 2, pp. 836838.
13. S. Trotz, W. J. Brown, B. G. Danly, J. P. Hogge, M. Khusid, K. E. Kreischer, M.
Shapiro and R. J. Temkin, “High Power Operation of a 17 GHz Photocathode RF
Gun,” Proc. Seventh Advanced Accelerator Concepts Workshop, Lake Tahoe, Oct.,
1996 (to be published).
14. S. Trotz, W. Brown, B. Danly, J. P. Hogge, K. E. Kreischer, M. Shapiro and R. J.
Temkin, “Experimental Operation of a 17 GHz Photocathode RF Gun,” Proc. 1997
Particle Accelerator Conf, IEEE Press (to be published, 1997).
15. S. Trotz, “Experimental Study of a 17 GHz High Gradient Photocathode Injector
Current Staff:
Scientists
•
•
•
•
•
•
•
•
•
•
Dr. Richard J. Temkin
Dr. Chiping Chen
Dr. John Machuzak
Mr. Ivan Mastovsky
Mr. William Mulligan
Dr. Michael A. Shapiro
Winthrop Brown
Stephen Korbly
Evgenya Smirnova
Jagadishwar Sirigiri
Scientist
Scientist
Scientist
Scientist
Scientist
Grad Student
Grad Student
Grad Student
Grad Student
Professor Richard J. Temkin (PI)
77 Massachusetts Avenue NW16-186
Cambridge, Massachusetts 02139
PHONE: 617/253-5528
Trapping
B reakdow n
Pulsed H eating (120 C )
Gradient (GeV/m)
1
MIT
0.1
CLIC
NLC HRC
0.01
SLC
0.001
1
10
100
Frequency (GHz)
Figure 1: Comparison of the accelerating gradients in the MIT 17 GHz RF Photocathode
gun (labeled “MIT”) compared with the gradients measured in other electron
accelerators such as the NLCTA and CLIC. Also shown is the gradient of the Haimson
0.5 m 17 GHz accelerator which is in operation at MIT.
Figure 2: The MIT 17 GHz Accelerator Laboratory showing the Haimson klystron (far
right), the Haimson 17 GHz accelerator (middle) and the 17 GHz RF Photocathode
electron gun (left).
Investigation of the Dynamics of Space Charge Dominated Beams
R.C.York – Michigan State University
Summary:
Since 1997, the National Superconducting Cyclotron Laboratory has collaborated with
the University of Maryland Electron Ring (E-Ring) project. This E-Ring will operate with
space-charge dominated beams aiming to explore the physics of beams with extreme
intensities and tune depression factors [1]. In addition to engineering support,
mechanical design, and fabrication of lattice hardware, the NSCL has also performed
simulation analyses for the E-Ring. Since 1999, our studies have been supported by
the U.S. Department of Energy with a particular emphasis on the development of
computer programs for the simulation of space charge dominated beam dynamics.
Our theoretical research activities include(d) the following topics:
• Single particle beam dynamics studies for the UMd E-Ring, using the DIMAD code
[2]. In the absence of the space charge the choice of the lattice working point (bare
tune) was evaluated including the effects of magnet multipoles, misalignments,
mispowering and the Earth’s magnetic fields effects. Correction schemes to minimize
the closed orbit distortion were also studied.
• High-order, 2D tracking, using the code COSY INFINITY [3,4]. Using a linear space
charge model, higher-order map analyses were done to explore the UMd E-Ring
performance under different space-charge conditions.
• Beam envelopes and dispersion matching for linear space charge model [5,6]. An
injection line was designed, providing a perfect matching of beam envelopes and the
dispersion function with those in the regular periodic UMd E-Ring structure. The
importance of matching for further beam dynamics in the ring was demonstrated.
• Improvement of a 2-D PIC code [6]. Modifications were made to allow arbitrary
conducting boundaries (free space, rectangular, circular); sector dipole, quadrupole,
sextupole and octupole magnets; fringing field model;
inclusion of momentum
spread. The code was used to simulate the beam through the injection line and
further tracking through 10 periods of the UMd E-Ring. The validity of the analytical
model for rms envelopes (item C) was evaluated.
• Development of a Slice Algorithm [7,8].
A novel computational approach was
developed to find longitudinal fields of bunched beams both quickly and accurately.
• Development of the Sub-3D PIC code [9,10]. A code for 3D beam dynamics
simulation that provides a significant reduction in computational time in comparison
with fully 3D models, without a concomitant loss of accuracy.
The tasks A-D have in large part been accomplished during 1999-2000. In general all
tasks will continue. Items A-D will shift in emphasis primarily to simulation studies in
support of UMd E-Ring experiments. Items E-F will continue to be primary code
development activities through the first half of 2001 shifting to simulation studies the
latter half of 2001.
1
Publications:
1.
M.Reiser et al. “The Maryland electron ring for investigating space-charge
dominated beams in a circular FODO systems”, in proceedings of IEEE Particle
Accelerator Conference, New York, A.Luccio and W.MacKay, eds., 1999, p. 234.
L.G.Vorobiev, X.Wu and R.C.York,“Single-particle beam dynamics studies for the
University of Maryland Electron Ring”, in proceedings of IEEE Particle Accelerator
Conference, New York, A.Luccio and W.MacKay, eds., 1999, p. 3116.
M.Berz “COSY INFINITY, Version 8”, Michigan State University Report No.
MSUCL-1088, November 1997.
X.Wu, L.G.Vorobiev and R.C.York, “Analysis of Space-Charge Effects in the
University of Maryland Electron Ring”, Michigan State University Report No.
MSUCL-1146, 2000.
L.G.Vorobiev and R.C.York,“Analysis of the injection line for the University of
Maryland electron ring, including dispersion and space charge”, Michigan State
University Report No. MSUCL-1122, 1999.
L.G.Vorobiev and R.C.York, “Numerical study of the injection line for the
University of Maryland electron ring”, Michigan State University Report No.
MSUCL-1136, 1999.
L.G.Vorobiev and R.C.York, “Numerical Technique to Determine Longitudinal
Fields of Bunched Beams within Conducting Boundaries”, Michigan State
University Report No. MSUCL-1117, 1998.
L.G.Vorobiev and R.C.York,“Calculation of longitudinal fields of high-current
beams within conducting chambers”, in proceedings of IEEE Particle Accelerator
Conference, New York, A.Luccio and W.MacKay, eds., 1999, p. 2781.
L.G.Vorobiev and R.C.York,“Algorithm for a fast Sub-3D Particle-In-Cell Code”,
Michigan State University Report No. MSUCL-1149, 2000.
L.G.Vorobiev and R.C.York, “Space charge calculations for sub-three-dimensional
particle-in-cell code”, Phys. Rev. ST Accel. Beams, 3, 114201 (2000).
2.
3.
4.
5.
6.
7.
8.
9.
10.
Current Staff:
•
•
•
Prof. Richard York:
Dr. Leonid Vorobiev:
Dr. Xiaoyue Wu:
Research Associate
Physicist
Richard C. York
National Superconducting Cyclotron Laboratory
Michigan State University
EAST LANSING MI 48824
PHONE:
FAX:
E-MAIL:
517/333-6325
517/353-5967
[email protected]
2
Figure 1: Injection lattice and several sectors of the UMd E-Ring (left). The scales are in
meters. The blackened circle denotes the input point into the injection system. The
dipole magnet labeled D1 is the injection point in the E-Ring.
Beam through the injection line (right). RMS beam envelopes σx (solid line - horizontal)
and σy (dashed line – vertical) and dispersion function Dx (dotted line) for the
perveance Q = 1.5x10-3 and σ δ = 1.5x10-2. The rms emittances are: εx,y=10-5 π m⋅rad.
Fig. 2 Beam bunch with total charge of 10-11 C and a longitudinally asymmetric charge
density inside a round metal pipe 4 cm in diameter.
Transverse Dimension [m]
0.02
0.01
0.00
-0.01
-0.02
-0.10
-0.05
0.00
0.05
0.10
0.15
Longitudinal Dimension Z (m)
Fig. 3 The space charge potential u (r , z ) (left) and the space charge electric field
Ez (r , z ) (right) as functions of “z” for different radii for the bunch of Fig. 2, using the
Slice Algorithm.
50
Off-axis Ez(r,z) [V/m]
Off-axis potential [V]
1.5
1.0
0.5
30
10
-10
-30
-50
0.0
-70
-0.2
-0.1
0.0
0.1
0.2
-0.2
Z-axis [m]
-0.1
0.0
Z axis [m]
3
0.1
0.2
Research Activities of MSU Beam Theory Group
M. Berz – Michigan State University
Summary:
Work in the Beam Theory and Dynamical Systems group at Michigan State University
comprises the following topics.
1. High-Order Maps with Verified Remainders. Methods are being developed
that allow determining high-order maps of accelerators with verified remainders.
Compared to other previously existing verified integrators, the new approach solves two
famous and important long-standing problems, namely the so-called dependency
problem1 and the so-called wrapping effect, both of which have substantial impact on
the behavior of the method in practice.
2. Minimal Symplectic Tracking. New methods have been developed that allow
the direct computation of a large class of arbitrary order extended generating functions
from high-order Taylor map and use them for symplectic tracking. Based on Hofer's
Metric and other tools, methods are derived that allow identifying the generators that
overall produce the smallest possible correction in the symplectification process. All new
generators significantly outperform the conventional four types routinely used.
3. COSY INFINITY. In the previous year, around 50 new users have registered for
the code, of which currently version 8 is being distributed.2 Support of the new as well
as the approximately 300 previously registered users continues to be one of the very
time demanding aspects of the work in the group. The code has also been used at the
US Particle Accelerator School and forms one of the backbones of the interactive
homework system3 of VUBeam, MSU's Virtual University program in Beam Physics
described below. New features that are being implemented in the code include the
refinements to the methods for the verified integration of maps,4 the ability to treat
detailed accelerating structures in connection with a collaboration with ANL, various
enhanced fringe field methods for the work on the Muon Collider described below, as
well as tools for the study of universal generating functions.
4. Contributions for the LHC and the Muon Collider. Various tools for the
detailed treatment of features of the LHC and the Muon Collider have been developed in
the last year, implemented in COSY, and used for simulations at FNAL, CERN, and MSU.
It has been shown that fringe field effects are of prime significance in the muon
collider5,6 and their correction is one of the more difficult tasks. It was also shown that
because of the large amplitude, it is important to include all nonlinear effects stemming
from the root function in the Hamiltonian, and to perform a full kinematic correction.7
5. Educational Activities. Besides the training of the graduate students within the
group, significant work is done for the development of VUBeam8,3 the on-line education
initiative in Beam Physics supported by MSU's Virtual University. Since the official launch
of the remote Master's and Ph.D. programs in Beam Physics in 1998, more than 60
remote students were enrolled in courses per year, which, has made Beam Physics the
largest graduate specialization area in the MSU Physics Department. In addition, there
are now around 20 external degree students admitted to the remote Master's and Ph.D.
programs. At the present time, these students are mostly taking courses and in the
future those on the Ph.D. track will be paired up with suitable mentors at US National
Laboratories and other locations to provide guidance and supervision for dissertation
work. Currently there are five on-line courses based on live lectures over the Internet
and videoconferencing and on downloadable Audio/Video files.
Publications:
1.
K. Makino and M. Berz, “Efficient control of the dependency problem based on
Taylor model methods,” Reliable Computing, 5:3-12, 1999.
2
K. Makino and M. Berz, “COSY INFINITY version 8,” Nuclear Instruments and
Methods, A427:338-343, 1999.
3
Martin Berz, Jens Hoefkens, Lars Diening and Bela Erdelyi, “The webcosy system
for course management in distance education,” Journal of Computers in
Mathematics and Science Teaching, 2000, in print.
4
M. Berz and K. Makino, “Verified integration of ODEs and flows with differential
algebraic methods on Taylor models,” Reliable Computing, 4:361-369, 1998.
5
K. Makino M. Berz and B. Erdelyi, “Fringe field effects in muon rings,” AIP CP,
530:3847.
6
F. Zimmermann, C. Johnstone, M. Berz, B. Erdelyi, K. Makino, and W. Wan,
“Fringe fields and dynamics aperture in muon storage rings,” Technical Report
95, Muon Collider Collaboration, BNL, 2000.
7
K. Makino and M. Berz, “Effects of kinematic correction on the dynamics in muon
rings,” AIP CP, 530:217-227.
8
M. Berz, B. Erdelyi, and J. Hoefkens, “Experience with interactive remote
graduate instruction in beam physics,” Journal of Interactive Learning Research,
10,1:49-58, 1998.
9
M. Berz, “Modern Map Methods in Particle Beam Physics,” Academic Press, San
Diego, 1999.
10
M. Berz and G. Hoffstätter. Computation and application of Taylor polynomials
with interval remainder bounds. Reliable Computing, 4:83-97, 1998.
11
M. Berz, “Differential Algebraic Techniques,” Entry in 'Handbook of Accelerator
Physics and Engineering', M. Tigner and A. Chao (Eds.). World Scientific, New
York, 1999.
12
M. Berz, “Higher Order Derivatives and Taylor Models, Entry in 'Encyclopedia of
Optimization,” Kluwer, Boston, in print.
13
M Berz, “Computational Differentiation, Entry in Encyclopedia of Computer
Science and Technology,' Marcel Dekker, New York, in print.
14
W. Wan and M. Berz, “Design of a fifth order achromat,” Nuclear Instruments
and Methods, 423-1:1-6, 1998.
15
W. Wan, C. Johnstone, J. Holt, M. Berz, K. Makino, and M. Lindemann, “The
influence of fringe fields on particle dynamics in the large hadron collider,”
Nuclear Instruments and Methods, A427:74-78, 1999.
16
M. Berz, B. Erdelyi, W. Wan, and K. Ng, “Differential algebraic determination of
highorder off-energy closed orbits, chromaticities, and momentum compactions,”
Nuclear Instruments and Methods, A427:310-314, 1999.
17
R. Degenhardt and M. Berz, “High accuracy description of the fringe field in
particle spectrographs,” Nuclear Instruments and Methods, A427:151-156, 1999.
18
M. Berz and K. Makino, “New methods for high-dimensional verified quadrature,”
Reliable Computing, 5:13-22, 1999.
19
M. Berz, “Nonarchimedean analysis and rigorous computation,” International
Journal of Applied Mathematics, 2:889-930, 2000.
20
K. Shamseddine and M. Berz, “Power series on the Levi-Civita field,”
International Journal of Applied Mathematics, 2:931-952, 2000.
21
M. Berz and J. Hoefkens, “Verified inversion of functional dependencies and
superconvergent interval Newton methods,” Reliable Computing, in print.
22
K. Shamseddine and M. Berz, “Convergence on the Levi-Civita field and study of
power series,” Proc. Sixth International Conference on Nonarchimedean Analysis,
2000, in print.
23
M Berz, “Analytical and computational methods for the Levi-Civita fields,” Proc.
Sixth International Conference on Nonarchimedean Analysis, 2000, in print.
21
M Berz, “Constructive generation and verification of Iyapunov functions around
fixed points of nonlinear dynamical systems,” IJCR, 2000, in print.
25
K. Makino, and M. Berz, “Global optimization with Taylor models,” IJCR,
submitted.
26
M. Berz, “Towards a universal data type for scientific computing,” Proc. AD2000,
SIAM, 2000, in print.
27
K. Makino and M. Berz, “New applications of taylor model methods,” Proc.
AD2000, SIAM, submitted.
28
J. Hoefkens and M. Berz, “Efficient high-order methods for odes and daes,” Proc.
AD2000, SIAM, 2000, in print.
29
J . Hoefkens and M. Berz, “Differential algebraic methods in feedforward control
theory,” Automatica, submitted.
30
K. Makino and M. Berz, “Pertubative equations of motion and differential
operators in nonplanar curvilinear coordinates,” International Journal of Applied
Mathematics, 2000, in print.
31
K. Makino and M. Berz, “Preservation of canonical structure in nonplanar
curvilinear coordinates,” International Journal of Applied Mathematics, 2000, in
print.
32
K. Shamseddine and M. Berz, “The differential algebraic structure of the
levi-civita field,” International Journal of Applied Mathematics, 2000, in print.
33
M . Berz, B. Erdelyi, and K. Makino, “Fringe field effects in small rings of large
acceptance,” Physical Review ST-AB, in print, 2000.
34
A. Geraci, T. Barlow, M. Portillo, J. Nolen, K. Sheppard, M. Berz, and K. Makino,
“Calculation of radio-frequency and electrostatic structures using map-oriented
beam optics,” Physical Review ST-AB, submitted.
35
K. Makino, M. Berz, and B. Erdelyi, “Towards accurate simulation of fringe field
effects. Nuclear Instruments and Methods,” in print, 2000.
36
B. Erdelyi and M. Berz, “Extended generating function symplectification for
order-by-order symplectic taylor maps,” Physical Review STLAB, submitted.
37
B. Erdelyi and M. Berz, “Nonlinear effects in muon accelerators,” Physical Review
ST-AB, submitted.
38
K. Makino and M. Berz, “Verified integration of transfer maps.” Physical Review
STLAB, submitted.
39
K. Makino, and M. Berz, “Verified integration of dynamics in the solar system.”
Nonlinearity, in print.
Talks:
1.
12/10/97, Martin Berz, "Experiences with International Distance Education",
National Research Council / National Academy of Science Panel on Distance
Education, Washington, invited talk
2.
02/98, Kyoko Makino, Seminar, Fermilab
3.
03/98, Bela Erdelyi, Seminar, Fermilab
4.
04/06/98, Martin Berz, "Nonlinear Effects in Accelerators: Fringe Fields,
Resonances, and Momentum Compaction and other delights", Seminar, Fermilab
5.
04/07/98, Martin Berz, "New Verified Methods for High-Performance Applications",
Seminar, Mathematics and Computer Science Division, Argonne National
Laboratory
6.
04/14/98, Martin Berz, "High-Order Maps and Bounds for Taylor Remainders", Fifth
Conference on Charged Particle Optics, Delft, Netherlands
7.
04/14/98, Martin Berz, "The Influence of Fringe Fields on Particle Dynamics in the
LHC", Fifth Conference on Charged Particle Optics, Delft, Netherlands
8.
04/15/98, Kyoko Makino, "COSY Infinity Version 8", Fifth International Conference
on Charged Particle Optics, Delft, The Netherlands
9.
04/21/98, Martin Berz, "Recent Advances in Differential Algebraic Methods", APS
Spring Meeting, Columbus, invited talk
10. 04/23/98, Kyoko Makino, "Verified High Order Numerical Integrators Based on
Taylor Models", International Conference on Interval Methods and their Application
in Global Optimization (INTERVAL'98), Nanjing, China, Invited talk.
11. 04/23/98, Kyoko Makino, "New Methods for High-Dimensional Verified
Quadrature", International Conference on Interval Methods and th30/98, Kyoko
Makino, "Rigorous Long-term Stability Estimates", BDO-98, Fifth International
Workshop, Beam Dynamics and Optimization, St. Petersburg, Russia, Invited talk.
12. 04/98, Kyoko Makino, Seminar, Fermilab
13. 05/07/98, Kyoko Makino, "Precise and Verified Calculation of High Order Transfer
Maps for General Fields", Seminar, KEK, Japan
14. 05/19/98, Martin Berz, "Verified Differentiation through ODE solvers", 1998
Computational Differentiation Theory Institute, Argonne, 11, invited talk
15. 05/20/98, Kyoko Makino, "Differential Algebraic Methods on Taylor Models",
Argonne Theory Institute on Differentiation of Computational Approximations to
Functions, Invited talk.
16. 04/23/98, Kyoko Makino, "Verified High Order Numerical Integrators Based on
Taylor Models", International Conference on Interval Methods and their Application
in Global Optimization (INTERVAL'98), Nanjing, China, Invited talk.
17. 04/23/98, Kyoko Makino, "New Methods for High-Dimensional Verified
Quadrature", International Conference on Interval Methods and their Application in
Global Optimization (INTERVAL'98), Nanjing, China, Invited talk.
18. 05/07/98, Kyoko Makino, "Precise and Verified Calculation of High Order Transfer
Maps for General Fields", Seminar, KEK, Japan
19. 05/20/98, Kyoko Makino, "Differential Algebraic Methods on Taylor Models",
Argonne Theory Institute on Differentiation of Computational Approximations to
Functions, Invited talk.
20. 06/04/98, Kyoko Makino, "Nonlinear Effects in Rings: Fringe Fields, Resonances,
Momentum Compactions, and Other Delights", Seminar at Fermilab
21. 06/30/98, Martin Berz, "Nonlinear Beam Dynamics - New Trends", 1998 Conference
on Beam Dynamics and Optimization, St. Petersburg, Russia, invited talk
22. 06/30/98, Kyoko Makino, "Rigorous Long-term Stability Estimates", BDO-98, Fifth
International Workshop, Beam Dynamics and Optimization, St. Petersburg, Russia,
Invited talk.
23. 07/15/98, Martin Berz, "Verified Integration under avoidance of the Wrapping
Effect", SIAM Annual Meeting, invited talk
24. 10/29/98, Martin Berz "Verified Integration of Orbits and Flows", Second MICS
Workshop on Predictability of Complex Systems, Albuquerque, NM, invited talk
25. 03/99, Khodr Shamseddine, Numerical Analysis Workshop, Beirut, Lebanon
26. 03/99, Khodr Shamseddine, Colloquium, Department of Mathematics, American
University Beirut, Lebanon
27. 03/23/99 "The Beam Physics Virtual University Initiative," APS Centennial Meeting,
Atlanta, invited talk
28. 05/13/99 "Verified Integration in Celestial Mechanics", SIAM Annual Meeting,
Atlanta, GA, invited talk
29. 05/13/99, Kyoko Makino, "Control of the Dependency Problem," SIAM Annual
Meeting, Atlanta, Invited talk.
30. 05/14/99 "The Taylor Model Method for Verified Integration of ODEs", Symposium
on Verified Integration, Atlanta, GA, invited talk
31. 08/05/99 "Dependency-Free Verified Methods", University of Aachen, Seminar,
Germany
32. 08/13/99 "New Methods for Verified Integration of ODEs", Eighth International
Colloquium for Numerical Analysis, Plovdiv, Bulgaria, invited talk
33. 08/15/99 "Experiences with On-Line Education in Beam Physics", International
Internet Education Workshop, Romania, invited talk
34. 08/12/99, Khodr Shamseddine, Eighth International Colloquium for Numerical
Analysis, Plovdiv, Bulgaria, invited talk
35. 10/01/99 "Fringe Field and Kinematic Effects in Muon Rings, 1999 Muon Collider
Collaboration Meeting, Montauk, New York, invited talk
36. 11/21/99 "Verified Integration of ODBs,
Verification, Dagstuhl, Germany, invited talk
Symbolic-Algebraic
Methods
and
37. 12/14/99, Kyoko Makino, "Effects of Kinematic Correction", Neutrino Factory and
Muon Collider Collaboration Meeting, Berkeley, Invited Talk
38. 12/16/99 "Nonlinear Effects in Muon Storage Rings, 1999 Muon Collider and
Neutrino Factory Conference, San Francisco, invited talk
39. 04/30/00, Bela Erdelyi, APS Spring Meeting, Long Beach, California
40. 05/01/00 "Effects of Fringe Fields on Muon Ring Dynamics, APS Spring Meeting,
Long Beach, California, invited talk
41. 05/24/00 "Nonlinear Effects in Neutrino Factories", Neutrino Factory Conference,
Monterey, California, invited talk
42. 06/11/00 "Verified Computational Methods", Symposium on Modern Methods in
Numerics, Maui, Hawaii, invited talk and tutorial
43. 06/14/00 "Verified Integration of Near-Earth Asteroids", WAC 2000, Maui, Hawaii,
invited talk
44. 06/21/00 "Towards a Universal Data Type for Scientific Computing", Automatic
Differentiation 2000, Nice, selected talk
45. 06/14/00, Kyoko Makino, "Verified Integration of Near-Earth Asteroids", World
Automation Congress, WAC2000, Maui, Hawaii
46. 06/23/00, Jens Hoefkens, AD2000, Nice, France
47. 06/23/00, Kyoko Makino, "New Applications of Taylor Model Methods", 3rd
International Conference on Automatic Differentiation, AD2000, Nice, France
48. 06/27/00, Kyoko Makino, "Verification of Invertibility and Charting of Constraint
Manifolds in Differential Algebraic Equations", 6th IMACS International IMACS
Conference on Applications of Computer Algebra, IMACS ACA 2000, St. Petersburg,
Russia
49. 06/27/00, Kyoko Makino, "Differential Algebraic Structures and Verification," 6th
IMACS International IMACS Conference on Applications of Computer Algebra,
IMACS ACA 2000, St. Petersburg, Russia
50. 06-00, Bela Erdelyi, 2000 Conference on Internet Education, Romania
51. 07/05/00, Kyoko Makino, "Verified Control of Near-Earth Asteroid Orbits", 11th IFAC
International Workshop, Control Applications of Optimization, CA02000, St.
Petersburg, Russia
52. 07/06/00, Martin Berz, "Analysis and Computational Methods for the Levi-Civita
Field," 2000 Conference on Non-Archimedean Analysis, Ioannina, Greece
53. 07/06/00, Kyoko Makino, "Dfferential Algebraic Methods for Feedforward Control
Theory", 11th IFAC International Workshop, Control Applications of Optimization,
CA02000, St. Petersburg, Russia, invited talk
54. 07/07/00, Kyoko Makino, "Nonlinear Effects on the Dynamics in Muon Storage
Rings", Beam Dynamics Optimization, BD02000, St. Petersburg, Russia, invited talk
55. 07/07/00, Kyoko Makino, "Nonlinear Spin Dynamics", Beam Dynamics Optimization,
BD02000, St. Petersburg, Russia
56. 07/08/00, Khodr Shamseddine, "Convergence on the Levi-Civita Field and Study of
Power Series", Sixth International Conference on P-adic Analysis, Ioannina, Greece
57. 07/10/00, Martin Berz, "Verified Integration and Taylor Model Methods in Nonlinear
Dynamics", WSES 2000, Vouliagmeni, Greece, invited talk
58. 07/12/00, Kyoko, Makino, "Verified Global Optimization with Taylor Model Methods",
WSES CSCC-MCP-MCME 2000, Athens, Greece, invited talk.
59. 07/15/00, Khodr Shamseddine, "Nm-Archimedean Analysis and Applications in
Physics", Center for Advanced Mathematical Sciences, American University of Beirut,
Beirut, Lebanon, Seminar
60. 07/21/00 "Verified Integration of ODEs", WCNA 2000, Catania, invited talk
61. 07/21/00, Kyoko Makino, "Higher Order Verified Inclusions of Multidimensional
Systems by Taylor Models", 3rd World Congress of Nonlinear Analysts, Catania, Italy
62. 08/10/00, Kyoko Makino, "Verified High Order Range Enclosure of Multivariate
Functions", BIT2000, Lund, Sweden
63. 08/10/00, Martin Berz, "Verified Integration of ODEs under practical avoidance of
the Wrapping Effect", BIT2000, Lund, Sweden
64. 08/13/00, Khodr Shamseddine, "The Differential Algebraic Structure of the LeviCivita Field and Applications", Ninth International Colloquium on Numerical Analysis
and Computer Science with Applications, Plovdiv, Bulgaria, Invited Talk
65. 08/15/00, Kyoko Makino, "Perturbative Equations of Motion and Differential
Operators in Non-planar Curvilinear Coordinates", Ninth International Colloquium on
Numerical Analysis and Computer Science with Applications, Plovdiv, Bulgaria,
Invited Talk
66. 08/15/00, Martin Berz, "Preservation of Hamiltonian Structure in 3D Curvilinear
Dynamics", 2000 Colloquium on Numerical Analysis and Computer Science, Plovdiv,
Bulgaria, invited talk
67. 08/28/00, Kyoko Makino, "Fringe Field Computation and COSY Infinity", Seminar at
KEK, Japan
68. 09/14/00, Bela Erdelyi, ICAP 2000, Darmstadt, Germany
69. 09/20/00 "Higher Order Verified Methods", SCAN2000 - Interval 2000, Karlsruhe,
Germany, invited talk
70. 09/18/00, Jens Hoefkens, SCAN2000, Karlsruhe, Germany
71. 09/13/00, Martin Berz, "Nonlinear Effects in Muon Storage Rings', International
Computational Accelerator Conference, Darmstadt, Germany
72. 09/19/00, Kyoko Makino, "Advances in Verified Integration of ODEs", SCAN2000 Interval 2000, Karlsruhe, Germany, Invited Talk
73. 09/20/00 "Higher Order Verified Methods", SCAN2000 - Interval 2000, Karlsruhe,
Germany, invited talk
74. 10/16/00, Martin Berz "Verified Computational Methods", Seminar, Kansas State
University, Manhattan, Kansas, Seminar
Current Staff:
•
Prof. Martin Berz
•
Dr. Kyoko Makino
Research Associate since Spring 1998
•
Dr. Khodr Shamseddine
Research Associate since December 1999
•
Dr. Alexander Ovsyannikov
Research Associate since Fall 2000
•
Bela Erdelyi
Graduate student since Fall 1996
•
Jens Hoefkens
Graduate student since Fall 1996
•
Abhishek Mehta
Graduate student. since Summer 2000
Prof. Martin Berz (PI)
170 Cyclotron
East Lansing, MI 48824
PHONE: (517) 355-9672x313
Instrumentation Standards
L. Costrell – NIST
Summary:
This small project at the National Institute of Standards and Technology (NIST) is quite
different from and is dwarfed by the much larger University and National Laboratory
projects of the Department of Energy. Its function is that of standards development,
processing and coordinating. Its first activity was the development of the NIM
instrumentation system, through the Department of Energy NIM Committee chaired by
Louis Costrell of NIST, who initiated the development. The NIM system (DOE/ER0457T) seems to age gracefully and, with some upgrades, is currently produced
commercially by many manufacturers and used in numerous laboratories worldwide. An
independent economics study several years ago concluded that the savings, as a
consequence of the development and use of NIM, amounted to several billion
U.S.dollars up to that time.
The NIM system was supplemented by the computer oriented CAMAC system
(IEEE/ANSI 583) that was initiated by the late Harry Bisby of the Harwell Laboratory. Its
development and implementation was a joint effort of the ESONE Committee of
European Laboratories and the NIM Committee. Later, the high energy physics
community asked the Committee to develop a high speed, high input capacity, and
highly versatile electronics system to accommodate the detectors being developed for
the new generation of high energy accelerators. The result was the FASTBUS system
(IEEE/ANSI-960, IEC 935) that then served the needs of the high energy laboratories.
The increasingly high speed, increased I/O, and other requirements for the detectors
for accelerators currently under construction pose an even more severe challenge such
that much of the early processing is to be done at the detector itself before the signals
are routed to the rack electronics. When FASTBUS was first used, some installations
utilized VME electronics though they suffered from incompatibilities, excessive level of
crosstalk, limited I/O, and other shortcomings. NIM members (primarily Barsotti of
Fermilab, Downing, formerly of the University of Illinois, and Costrell of NIST) together
with Parkman of CERN, worked with the VME Standards Organization (VSO) that has
upgraded VME to provide an economical, high capability electronics system that
overcomes many of the former limitations. Thus the current VME64extensions standard
is suitable for many demanding applications, including those of the HEP community.
Additionally NIM, in collaboration with CERN and KEK has produced a guide for VME for
physics applications (DOE/SC-0013 - 27 September 1999, Designer & User Guide for
ANSI/VITA 23-1998 -VME64 Extensions for Physics and Other Applications [VME64xP]).
As the VSO continues its work with VME, NIM continues involvement so as maximize
VME’s applicability for physics experiments. NIM also continues collaboration with
European and Asian colleagues and will be discussing with them future physics
instrumentation needs. The DOE/ NIST project continues to provide administrative
maintenance of the NIM Committee and its standards.
Publications:
1. E.J. Barsotti, R. W. Downing, Louis Costrell, and Christopher Parkman (Editors),
DOE/SC-0013-27 September 1999, Designer & User Guide for ANSI/VITA 23-1998 –
VME64 Extensions for Physics and Other Applications [VME64xP]
Staff:
Costrell, Louis
Unterweger, M.P.
P.I.
Physicist
Louis Costrell
National Institute of Standards and Technology
Ionizing Radiation Division
100 Bureau Drive
GAITHERSBURG, MD 20899-8460
PHONE:
FAX:
E-Mail:
301-975-5608
301-869-7682
[email protected]
Electromechanical Properties of Superconductors
Jack Ekin - NIST
Summary:
Project Purpose: This project provides the electromechanical research needed to
develop YBCO and BSCCO superconductors for high-field magnet and electric power
applications. Stress and strain management is one of the key base technologies that need
to be developed for these brittle ceramic materials. The project utilizes unique
measurement capabilities to study and develop models for understanding
electromechanical properties. The results are needed to provide performance feedback to
the organizations developing the conductors (LBL, ORNL, LANL, ANL, and the companies
collaborating with them), as well as providing engineering design data for their use in DOE
applications. DoE/High Energy Physics, NIST, and DoE/Energy Efficiency provide cost
sharing for this program.
Accomplishments for FY 2000:
(1) The first static transverse stress data in Bi-2212 were obtained on a wide variety of
conductors, which showed highly variable and significant Jc degradation.
(2) Data on the static transverse fatigue effect in Bi-2223 were published in the Jour. of
Appl. Phys. and preliminary reports on the effect in coated conductors were given at
several conferences.
(3) The first transverse cyclic fatigue tests were made in all three HTS systems (Bi-2223,
Bi-2212, and YBCO coated conductors).
(4) All the measurements problems in static transverse stress testing were solved and the
first definitive data were obtained on a series of IBAD conductors which showed
excellent transverse tolerance beyond 120 MPa.
(5) 2 more chapters for the textbook were completed and reviewed by three experts and
two students. A third chapter on construction techniques is under preparation.
Brief Description: The first definitive transverse stress data on a series of coated data
having high critical-current sensitivity Jc of over 1 MA/cm2 and high n values (indicated
minimal defects). The Jc degradation for static transverse stress was less than 1% for a
series of IBAD conductors subjected to monotonic loading. Using a second measurement
protocol, where the load was incremented in steps separated by unloading, the degradation
was less than 5%. The second case is more severe than the first because frictional support
of the pressure surface is not available to suppress in-plane yielding.. This represents very
good transverse stress tolerance for these coated conductors. A pure soft Ni substrate
RABiTS coated conductor was also tested. The Jc degradation from transverse stress was
less than 6% at static stress loads of 100 MPa, but showed significant degradation at
transverse loads above 100 MPa. This represents remarkably good transverse stress
tolerance for such soft Ni substrates up to 100 MPa, although significant mechanical
damage appears to occur at higher stress.
The first static transverse stress data were also obtained on a series of Bi-2212 conductors.
The results showed that these conductors have widely scattered results, with Jc
degradation between 15% and 35% at 100 MPa. All of these conductors had relatively
high Jc values to start with, indicating that high Jc does not necessarily indicate high strain
tolerance. These results in Bi-2212 can be contrasted with the effect of transverse stress
in Bi-2223. A series of Bi-2223 tape samples showed good transverse stress tolerance,
with a Jc degradation between 3% and 10% at 100 MPa.
This year, the first studies of cyclic transverse stress effects on the critical current of Bi2223, Bi-2212, and YBCO coated conductors were made. The fatigue tolerance of Bi-2223
was variable. In one case the degradation was only 3.4% after 2000 cycles at 100 MPa.
In another case there was little fatigue degradation at first (~2.6% between 1 and 10
cycles) followed by a large 30% drop between 10 and 100 cycles. Beyond 100 cycles,
there was little additional degradation out to 200 cycles (<3%). For Bi-2212 the response
was also variable, amounting in the best case to about an 8% fatigue degradation after
2000 cycles at 100 MPa. The results for IBAD coated conductors showed less than 2%
degradation in Jc after application of 2000 cycles of 122 MPa transverse stress. This data
were for films with a YBCO thickness of ~ 0.9 µm thick. For IBAD coated conductors
having a YBCO film thickness of 0.9 µm, the fatigue tolerance appears to be very good.
Work is progressing on the writing of an experimental techniques textbook. Included in
this year’s effort is a chapter giving detailed techniques for fabricating high quality HTS
contacts, which is particularly relevant to the problem of measuring critical currents in the
new thicker-film coated conductors. The treatise includes descriptions of contacts for both
high-current superconductors and thin films. Detailed information is given on techniques
for surface preparation, contact pad deposition, and contact annealing. Methods for
determining spreading resistance effects are also presented, along with an example
calculation of the minimum contact area needed for critical-current measurements.
Handbook data are compiled on contact resistivities, bulk resistivity of noble-metal contact
pads, common solders, and superconductor matrix materials at room temperature, liquid
nitrogen, and liquid helium temperatures.
Publications:
(1) J. W. Ekin, S. L. Bray, N. Cheggour, C. Clickner, S. Foltyn, and P. Arendt, “Transverse
Stress and Fatigue Effects in YBCO-Coated IBAD Tape,” Applied Superconductivity
Conf., Sept. 17-22, 2000, IEEE Trans. Appl. Superconducvity, to be published.
(2) J. W. Ekin, “Superconductor Contacts,” Handbook of Superconducting Materials,
Institute of Physics Pub., England, to be published.
(3) S. L. Bray, J. W. Ekin, C. Clickner, and L. Masur, "Transverse Compressive Stress
Effects on the Critical Current of Bi-2223/Ag tapes reinforced with pure Ag and oxidedispersion-strengthened Ag,” Jour. Appl Physics 88, p. 1178 (2000).
(4) P. E. Kirkpatrick, J. W. Ekin, and S. L. Bray, “A Flexible High-Current Lead for Use in
High Magnetic Field Cryogenic Environments,” Rev. Sci. Instr. 70, 3338 (1999).
(5) Yizi Xu, C. C. Clickner, R. L. Fiske, and J. W. Ekin, “Oxygen annealing of YBCO/Gold
Thin-Film Contacts," Adv. in Cryog. Eng. 44, 381-388 (1998).
(6) S. L. Bray, J. W. Ekin, and M. J. Nilles, "Fatigue-Induced Electrical Degradation of
Composite High-Purity/High-Strength Aluminum Rings at 4 K," Adv. in Cryog. Eng. 44,
315-322 (1998).
(7) S. L. Bray, J. W. Ekin, and R. Sesselmann, "Tensile Measurements of the Modulus of
Elasticity of Nb3Sn at Room Temperature and 4 K," IEEE Trans. Appl. Super. 7, 1451
(1997).
(8) S. C. Sanders, J. W. Ekin, and B. Jeanneret, "Pt Buffer Layer for Protecting YBCO from
Al at Annealing Temperatures up to 450oC, Adv. in Cryo. Eng. 42, 877 (1997).
(9) J. W. Ekin, S. L. Bray, C. C. Clickner, and N. F. Bergren, "High Compressive Axial Strain
Effect on the critical Current and Field of Nb3Sbn Superconductor Wire," Adv. in Cryo.
Eng. 42, 1407 (1997).
Current Staff:
•
•
•
•
•
Dr. Jack Ekin
Dr. N. Cheggour
Dr. Y. Xu,
C. Clickner
R. Sesselmann
P.I. 303-597-5448, [email protected]
Physicist 303-497-3815, [email protected]
Physicist
303-497-7894, [email protected]
Research Technician
Graduate Student
Dr. Jack Ekin (PI)
National Institute of Standards and Technology
MS 724.05
325 Broadway
Boulder, Colorado 80303
PHONE: 303/497-5448
FAX: 303/497-5316
Development of a Thermionic Magnicon at 11.4 GHz
S.H. Gold – Naval Research Lab
Summary:
The goal of this program is to develop a new type of accelerator-class microwave
amplifier tube for use in future colliders or other high-gradient linear accelerators. The
magnicon, originally invented at the Budker Institute for Nuclear Physics (INP) in
Novosibirsk, Russia, is a “scanning-beam,” or deflection-modulated amplifier tube that
offers the potential for high power and very high efficiency at frequencies ranging from
1 to 35 GHz. Unlike proposed fast-wave high-frequency alternatives to the klystron, the
magnicon performance can exceed that of high power klystrons even at lower
frequencies. Compared to klystrons, its potential advantages include: 1) higher
efficiency, because of the use of a synchronous interaction that does not require beam
bunching; 2) higher power, because of the potential for operating at higher perveance
without loss of efficiency; 3) longer output pulse lengths (which would permit higher
levels of microwave pulse compression to be employed), because of the lower fields in
the output cavity and the lack of current interception on the rf circuit; and 4)
insensitivity to mismatched loads. Experiments at the INP have demonstrated 2.6 MW
at 915 MHz with 73% efficiency in a 30-µs pulse, and 55 MW at 7 GHz with 55%
efficiency in a 1.1-µs pulse. The goal of the present program at the Naval Research
Laboratory (NRL) is to produce >60 MW at 11.424 GHz in a 1–µs pulse at 10 Hz with an
efficiency of >60% and >60-dB gain, using a 480–kV, 210–A, 2-mm-diameter electron
beam produced from a special ultrahigh–convergence electron gun.
The NRL program is being carried out as a collaboration with Omega-P, Inc. of New
Haven, CT, which has been separately supported under the DoE SBIR program.
Through this collaboration, the program has grown to include a number of the experts
that took part in the original INP magnicon experiments. It has also been broadened to
include the development and testing of special high-power X-band components that are
of interest for future colliders, including active microwave pulse compressors that are
capable of efficient compression ratios of 10-20x, much higher than that possible
through passive compressors such as SLED. The research on active pulse compressors
has brought in additional collaborators from the Institute of Applied Physics in NizhnyNovgorod, Russia. The pulse compression experiments will be carried out at the NRL
magnicon facility following demonstration of high-power output.
In the 11.4-GHz magnicon, an initially linear beam is “spun up” in a series of deflection
cavities containing synchronously rotating modes. There are a drive cavity, three gain
cavities, and finally two penultimate cavities, which contain high fields and do the bulk
of the spin-up. These cavities all operate at 5.7 GHz. The output cavity contains a
synchronously rotating 11.4-GHz mode. The experimental parameter that most directly
impacts magnicon efficiency is the size of the electron beam, with a near-Brillouin beam
needed to maximize the efficiency. Accordingly, one of the key technical
accomplishments is to demonstrate such a beam. In experiments carried out in 1999, a
beam diameter of 2.2 mm was demonstrated for a 450-keV, 190-A beam from a Piercetype electron gun jointly developed by Omega-P, Inc. and Litton Electron Devices. A
small gun asymmetry prevented achievement of the sub-2-mm beam predicted by the
electron optics design. Tests of the complete magnicon tube began in the summer of
1999, and during conditioning, demonstrated high deflection-cavity gain and stable
operation. However, before achieving more than 5 MW of output power, a collector
failure halted the experiment during rf conditioning, damaging the electron gun. The
repaired electron gun, with its asymmetry corrected, was tested in September, 2000,
and demonstrated improved symmetry at a beam diameter of ~2 mm. New tests of
the complete magnicon circuit began in November, 2000.
Publications:
1.
2.
3.
4.
5.
6.
S. H. Gold, A. K. Kinkead, and O. A. Nezhevenko “Compact All-Metal HighVacuum Gate Valve for Microwave Tube Research,” Review of Scientific
Instruments, 70(9): 3770-3773, 1999.
S.H. Gold, O.A. Nezhevenko, V.P. Yakovlev, A.K. Kinkead, A.W. Fliflet, E.V.
Kozyrev, R. True, R.J. Hansen, and J.L. Hirshfield, “Status Report on the 11.424
GHz Magnicon Amplifier,” in High Energy Density Microwaves, AIP Conference
Proceedings 474, R.M. Phillips, ed. (American Institute of Physics, Woodbury, NY,
1999), pp. 179–186.
O.A. Nezhevenko, V.P. Yakovlev, J.L. Hirshfield, E.V. Kozyrev, S.H. Gold, A.W.
Fliflet, A.K. Kinkead, R.B. True, and R.J. Hansen “X-Band Magnicon Amplifier,” in
Proceedings of the 1999 Particle Accelerator, A. Luccio and W. MacKay, eds., vol.
2, pp. 1049–1051.
A.L. Vikharev, A.M. Gorbachev, O.A. Ivanov, V.A. Isaev, S.V. Kusikov, L. Kolysko,
A.G. Litvak, M.I. Petelin, J.L. Hirshfield, O.A. Nezhevenko, and S.H. Gold, “100
MW Active X-Band Pulse Compressor,” in Proceedings of the 1999 Particle
Accelerator Conference, A. Luccio and W. MacKay, eds., vol. 2, pp. 1474–1476.
S.H. Gold, A.K. Kinkead, O.A. Nezhevenko, and V.P. Yakovlev, “System for
Measuring the Size of High Current Density Solid Electron Beams,” IEEE
Transactions on Plasma Science, 28(3): 657–664, 2000.
G.S. Nusinovich and S.H. Gold, “Summary Report of Working Group 6—MillimeterWave Sources,” in Proceedings of the Ninth Workshop on Advanced Accelerator
Concepts, Santa Fe, NM, 2000, in press.
Current Staff:
•
•
•
•
•
•
Gold, SH
Kinkead, AK
Fliflet, AW
Nezhevenko, OA
Yakovlev, VP
Hirshfield, JL
PI
Engineer
Physicist
Physicist, collaborator via DoE SBIR program
Steven H. Gold (PI)
Code 6793
Naval Research Laboratory
4555 Overlook Ave SW
WASHINGTON DC 20375-5346
PHONE:
FAX:
E-MAIL:
202/767-4004
202/767-3950
[email protected]
11.424 GHz Magnicon Experiment
Focused Transport of Space-Charge-Dominated Beams
Summary:
I. Haber - NRL
The increased beam luminosities characteristic of several newer particle accelerator
designs has increased the potential importance of adequately understanding and
predicting the influence of space charge forces on the beam dynamics. At moderate
luminosities, it is often possible to treat space charge as a smoothed perturbation on
the average force seen by each particle in the beam. However, as luminosity increases,
this approach becomes inadequate. When the self space-charge forces become
comparable to the external focusing fields which are used to contain the beam, new
space-charge collective degrees of freedom must be considered in describing the beam
evolution.
Analytic treatment of the nonlinear collective behavior characteristic of space-chargedominated beams has generally required the assumption of specific initial conditions
which do not always adequately describe what is observed experimentally. The
approach here employs simulation techniques that have been rendered credible in
extensive benchmarking against experiment since the current research program began
in 1978. Systematic comparison have been conducted between simulation and
experiments at the University of Maryland (UMd), as well as at the Heavy Ion Fusion
Virtual National Laboratory (HIF VNL). This approach has been used to build the
combined plasma physics/accelerator code WARP, which is the current simulation
workhorse.
Recent Research
Current research has continued to benefit from strong collaboration with personnel at
both the UMD, as well as at the laboratories comprising the HIF VNL. Motivated by the
continuing need for simulations to explain experimental data and for the design of
future experimental facilities, ongoing refinements have been made to simulation
abilities. Significant refinements have been spawned by increased understanding of the
importance of space charge collective modes. These modes introduce a new set of
characteristic frequencies on the beam system that can resonate either with the particle
betatron motion or be driven by the external structure. In extreme examples the beam
can be driven unstable and be substantially disrupted. More typically, the beam
emittance will grow, resulting in a dilution of beam luminosity.
Another significant implication of the excitation of space-charge collective modes is the
importance of specifying the variation of temperature or pressure within the beam, as
well as density. Numerous experimentally observed features of beam evolution were
understood only when the initial temperature variation was incorporated into the
simulation model. Inhomogeneities in transverse beam characteristics that were
observed experimentally were found to result from such temperature variations.
While the importance of these space charge collective phenomena to the large body of
existing accelerator designs has not been systematically investigated, several such
phenomena have been observed in a number of space-charge dominated experiments.
An example is the launching and propagation of radial density waves. As machine
luminosities are increased, these phenomena are likely to become commonplace,
especially in the source region of high luminosity machines.
Publications:
1. I. Haber, A. Friedman, D. P. Grote, S. M. Lund, s. Bernal, R. A. Kishek, “Recent
Progress in Heavy Ion Fusion Simulations,” to be published in Nucl. Instr. and Meth,
in Phys Res. A.
2. R. A. Kishek, S. Bernal, P. G. O’Shea, and M. Reiser., I. Haber, “Transverse SpaceCharge Modes in Non-Equilibrium Beams,” to be published in Nucl. Instr. and Meth,
in Phys Res. A.
3. D. P. Grote, A. Friedman, G. Craig, I. Haber, W. M. Sharp, “Progress Toward Sourceto-Target Simulation,” to be published in Nucl. Instr. and Meth, in Phys Res. A.
4. J. J. Barnard et al., Planning for an Integrated Research Experiment,” to be
published in Nucl. Instr. and Meth, in Phys Res. A.
5. I. Haber, A. Friedman, D. P. Grote, S. M. Lund, and R. A. Kishek, “Recent Progress
in the Simulation of Heavy Ion Beams,” Phys. Plasmas, Vol. 6, (May, 1999) 2254.
6. S. Bernal, R. A. Kishek, M. Reiser and I. Haber, Observations and Simulations of
Transverse Density Waves in a Collimated Space-Charge Dominated Electron Beam,”
Phys. Rev. Lett., Vol. 82, (May, 1999), 4002.
7. S. Bernal, P. Chin, R. A. Kishek, Y. Li, M. Reiser, J. G. Wang, T. Godlove, and I.
Haber, “Transport of a Space-Charge Dominated Electron Beam in a Short
Quadrupole Channel,” Phys. Rev. Special Topics, Accelerators and Beams, 1, #4,
(Aug. 1998).
8. I. Haber, D. A. Callahan, A. Friedman, D. P. Grote, S. M. Lund, T. F. Wang,
“Characteristics of an Electrostatic Instability Driven by Transverse-Longitudinal
Temperature Anisotropy,” Nucl. Instr. and Meth, in Phys Res. A, 415,405 (1998).
9. J. G. Wang, S. Bernal, P. Chin, ,T. F. Godlove, I. Haber, R. Kishek, Y. Li, M. Reiser,
M. Venturini, R. C. York, Y. Zou., “Studies of the Physics of Space-ChargeDominated Beams for Heavy Ion Inertial Fusion,” Nucl. Instr. and Meth, in Phys Res.
A, 415, 422, (1998).
10. R. A. Kishek, , S. Bernal, M. Reiser, M. Venturini, J. G. Wang, I. Haber, T. F.
Godlove, “Beam Dynamics Simulations of the University of Maryland E-Ring Project,”
Nucl. Instr. and Meth, in Phys Res. A, 415,417 (1998).
11. Alex Friedman, John J. Barnard, David P. Grote, and Irving Haber, “Simulation
Studies of Transverse-Resonance Effects in Space-Charge Dominated Beams,” Nucl.
Instr. and Meth, in Phys Res. A, 415,455 (1998).
12. David P. Grote, Alex Friedman, Irving Haber, William Fawley and Jean Luc Vay,
“New Developments in WARP: Progress Toward End-to-End Simulation,” Nucl. Instr.
and Meth, in Phys Res. A, 415,428 (1998).
13. S. M. Lund, J. J. Barnard, G. D. Craig, A. Friedman, D. P. Grote, H. S. Hopkins, T. C.
Sangster, W. M. Sharp, S. Eylon, T. J. Fessendon, E. Henestroza, S. Yu, I. Haber
“Numerical Simulation of Intense-Beam Experiments at LLNL and LBNL,” Nucl. Instr.
and Meth, in Phys Res. A, 415,345 (1998).
14. A. Seidl, C. M. Celata, W. W. Chupp, A. Faltens, W. M. Fawley, W. Ghiorso, K. Hahn,
E. Henestroza, S. MacLaren, C. Peters, D. Grote, and I. Haber, “Progress on the
Scaled Beam-Combining Experiment at LBNL,” Nucl. Instr. and Meth, in Phys Res. A,
415, 243 (1998).
Irving Haber (PI)
Code
4555 Overlook Avenue SW
Washington, DC 20375-5000
PHONE: 202/767-3198
FAX: 202/767-0631
High Energy Laser-Driven Acceleration Based on
the Laser Wakefield Accelerator
P. A. Sprangle Plasma Physics Division, Naval Research Laboratory (NRL)
Summary:
Overview: The NRL program addresses key theoretical and experimental issues
pertaining to the laser wakefield accelerator (LWFA) with the long term goal of
achieving acceleration of electrons to ~1 GeV. The program addresses issues of optical
guiding, wakefield generation, laser-plasma instabilities, and the injection, acceleration,
and phase slippage of beam electrons. Recent work has emphasized relevant issues for
next generation channel-guided LWFAs. The NRL experimental program is centered on
the Tabletop Terawatt (T3) laser, whose peak power is in the final stages of being
upgraded from 2.5 TW to 20 TW. Experiments include laser wakefield acceleration,
long range optical guiding of intense laser pulses in plasma-filled capillaries, and the
demonstration of an all-optical injector.
History: NRL has been carrying out theoretical research on laser-driven accelerators
since the late 1980s. Early work in this field included the source dependent expansion
(SDE) method for treating laser propagation, basic theory of LWFA’s, relativistic guiding,
optical guiding in plasma channels, and the first simulations of the self-modulated (SM)
LWFA. Other more recent achievements include studies of laser hose and modulation
instabilities, simulations of guiding in capillary discharge channels, trapping and
acceleration in SM-LWFAs and colliding pulse injectors, and analyses of ultrashort pulse
length corrections to the paraxial wave equation. Past experiments on the NRL T3 laser
have demonstrated wakefield generation, relativistic optical guiding, the generation of
100 MeV electrons in a SM-LWFA, and guiding of a probe pulse channel created by the
SM-LWFA. A related program on the vacuum beatwave accelerator lead to
development of the LIPA (Laser Ionization and Pondermotive Acceleration) optical
injector.
Recent achievements: Theoretical and numerical research during the past year has
included three task areas. The high gain (~1 GeV) accelerator work has included quasistatic simulations and analytical scaling laws in the standard LWFA regime, analysis of
tapered density channels, and analysis of a new channel-guided, self-modulated LWFA
concept. A new segmented capillary discharge design provides a method for generating
tapered density channels while providing a method for producing very long (>>10 cm)
channels. Studies on the propagation in plasma channels task area has included
analyses of modulation instabilities, pondermotive channelling and self-focusing, new
pulse compression and shaping concepts, and channel-guided inverse Cherenkov
accelerators. Work in the ionization effects task area has included simulation of
ionization front triggering of Raman instabilities and analysis of ionization physics in
LIPA. Much of the effort was centered on two major new simulations, the TurboWAVE
particle simulation and the SIMLAC 3-D nonlinear laser propagation code.
Experimental work during the past year involved channel guiding, LIPA, and the 20 TW
upgrade. Channel propagation studies included guiding experiments employing laser
wall ablation of a capillary wall and detailed diagnostics of density channels produced
by relativistically self-focused T3 laser pulses. LIPA studies included considerable
improvements in electron energy measurements and simulations of planned future
experiments. Initial experiments with the compressed 400 fs, 8 joule pulse are expected
in October, 2000.
Publications:
1. K. Krushelnick, C. I. Moore, A. Ting and H. R. Burris, “Frequency mixing of high
intensity laser light with stimulated Raman backscatter radiation in underdense
plasmas”, Phys. Rev. E 58, 4030 (1998).
2. E. Esarey, B. Hafizi, R. Hubbard and A. Ting, “Trapping and Acceleration in SelfModulated Laser Wakefields”, Phys. Rev. Lett. 80, 5552 (1998).
3. P. Sprangle, B. Hafizi, and P. Serafim, “Dynamics of Short Laser Pulses Propagating in
Plasma Channels,” Phys. Rev. Lett. 82, 1173 (1999).
4. P. Sprangle and B. Hafizi, “Guiding and Stability of Short Laser Pulses in Partially-Stripped
Ionizing Plasmas”, Phys. Plasmas 6, 1683 (1999).
5. P. Sprangle, B. Hafizi and P. Serafim, “Propagation of Finite Length Laser Pulses in
Plasma Channels,” Phys. Rev. E. 59, 3614 (1999).
6. Y. Ehrlich, C. Cohen, D. Kaganovich, and A. Zigler, R.F. Hubbard, P. Sprangle, and E.
Esarey, “Guiding and Damping of High-Intensity Laser Pulses in Long Plasma Channels,” J.
Opt. Soc. Am. B 15, (1998).
7. C. I. Moore, A. Ting, S. J. McNaught, J. Qiu, H. R. Burris and P. Sprangle, “A Laser
Accelerator Injector based on Laser Ionization and Ponderomotive Acceleration of
Electrons (LIPA)”, Phys. Rev. Lett., 82, 1688 (1999).
8. D. Kaganovich, A. Ting, C. I. Moore, A. Zigler, H. R.Burris, Y. Ehrlich, R. Hubbard
and P. Sprangle, “High Efficiency Guiding of Terawatt Sub-picosecond Laser Pulses
in a Capillary Discharge Plasma Channel”, Phys. Rev. E, 59, R4769 (1999)
9. B. Hafizi, A. Ganguly, J. Hirshfield, C. Moore and A. Ting, "Analysis of Gaussian
beam and Bessel beam driven vacuum beat wave accelerator", Phys. Rev. E 60,
4779 (1999)
10. C. I. Moore, K. Krushelnick, A. Ting, H. R. Burris, R. F. Hubbard and P. Sprangle,
“Transverse modulation of an electron beam generated in self-modulated laser
wakefield accelerator experiments”, Phys. Rev. E 61, 788 (2000).
11. P. Sprangle, B. Hafizi and J. R. Peñano, “Laser Pulse Modulation Instabilities in
Plasma Channels”, Phys. Rev. E. 61, 4381, (2000).
12. B. Hafizi, A. Ting, P. Sprangle and R. F. Hubbard, Relativistic Focusing and Ponderomotive
Channeling of Intense Laser Beams", Phys. Rev. E, accepted for publication (2000).
13. R. F. Hubbard, P. Sprangle and B. Hafizi, "Scaling of Accelerating Gradients and Dephasing
Effects in Channel-Guided Laser Wakefield Accelerators", to appear in IEEE Trans. Plasma
Sci., August (2000).
14. R. F. Hubbard, D. Kaganovich, B. Hafizi, C. I. Moore, P. Sprangle, A. Ting and A.
Zigler, "Simulation and Design of Channel-Guided Laser Wakefield Accelerators",
submitted to Phys. Rev. E (2000).
15. P. Sprangle, B. Hafizi, J. Peñano, R. F. Hubbard, A. Ting, A. Zigler and T. Antonsen, "Stable
Laser Pulse Propagation in Plasma Channels for GeV Electron Acceleration", submitted to
Phys. Rev. Lett. (2000).
16. P. Serafim, P. Sprangle and B. Hafizi, "Optical Guiding of a Radially Polarized Laser Beam
for Inverse Cherenkov Acceleration in a Plasma Channel", to appear in IEEE Trans. Plasma
Sci., August (2000).
17. D. Kaganovich, A. Zigler, R. F. Hubbard, B. Hafizi, J. Peñano, P. Sprangle, and A.
Ting, “Phase Control and Staging in Laser Wakefield Accelerators Using Segmented
Capillary Discharges,” to be submitted to Phys. Rev. Lett. (2000).
Current Staff:
Personnel (Theoretical Numerical)
•
•
•
•
•
Phillip Sprangle
Richard F. Hubbard
Bahman Hafizi
Daniel Gordon1
Joseph Peñano
Principal Investigator, NRL Code 6790
NRL Code 6791
Icarus, Inc.
NRL/NRC Postdoctoral fellow
LET, Corp.
Personnel (Experimental)
•
•
•
•
1
2
Antonio Ting
Christopher Moore
Theodore Jones
Dmitri Kaganovich2
NRL Code 6795
NRL Code 6795
NRL Code 6795
LET, Corp.
Stipend is paid by NRC fellowship program
Will join group in October, 2000, after receiving Ph.D. from Hebrew University.
Dissertation research was partially funded by this program for experiments performed
at NRL.
Dr. Philip A. Sprangle
Code 6790
4555 Overlook Avenue SW
Washington, DC 20375-5346
PHONE: 202/767-3493
FAX: 202/767-0631
Materials, Strands, and Cables
For Superconducting Accelerator Magnets
E.W. Collings and M.D. Sumption – Ohio State University
Summary:
Task-I--- Materials: The focus of Task-I is Nb3Al. Numerous processing details are
studied including:
(a) the role of precursor laminate size and the meaning of an "effective laminate size"
that seems to govern the high temperature diffusion reaction kinetics, and the
possible advantage of a preliminary heat treatment (HT);
(a) the optimal Nb:Al atomic ratio in the interests of obtaining stoichiometric A15 plus
flux pinning precipitates (in addition to grain boundaries);
(a) in the high temperature process, the optimal pre-quench temperature (Tmax) and the
location of Nb/Al's pre-quench condition in one or other of the existing Nb-Al phase
diagrams;
(a) ternary substitutions, quench rate, and the nature of the bcc→A15 so-called
ordering HT.
Task-II --- Strands: Several important strand-based phenomena are studied,
including:
(a) Flux jumping and bridging, consisting of (i) magnetic study of flux jumping (FJ) in
Nb3Sn and Nb3Al strands, and the role played by the internal Nb structure, (ii) an
investigation into the adequacy of the adiabatic description of FJ, an enquiry into
the stabilizer/SC ratio needed to ensure dynamic FJ stability or cryostability as the
case may be, and into ways of incorporating additional stabilization especially in the
case of Nb3Al; (iii) a magnetic approach to the characterization of bridging
"strength" and a comparison of the results with conventional (magnetic/transport)
determinations of effective filament diameter (deff).
(a) Influences of Strand Design and Operating Temperature on Eddy Currents in
Multifilamentary LTSC and HTSC Strands consisting of: (i) the influence of
temperature on eddy current loss in relationship to filament/matrix interface
resistance in MF NbTi/Cu strands and (related to this) the temperature dependence
of effective matrix resistivity of MF HTSC/Ag strands; (ii) the influence of aspect
ratio on eddy current loss in MF HTSC/Ag strands and furthermore the influence of
"internal architecture" (i.e. number density of filaments and filament aspect ratio)
on that loss; (iii) an examination of the properties of twisted MF HTSC strands with
a central insulating core, and the manner in which they are electrically similar to
core-type Rutherford cables.
Task-III --- Cables: This is a continuing study of: innovative cable designs to control
coupling loss, further measurements and analysis of AC loss in cables, and the
formulation and implementation of an extension of the "standard" (Sytnikov) model for
coupling loss.
Publications:
Published in 1999:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
E. W. Collings, M. D. Sumption, R. M. Scanlan, and L. R. Motowidlo, "Low
coupling loss core-strengthened Bi:2212/Ag Rutherford cables," IEEE Trans.
Appl. Supercond., 9: 758-761, 1999.
R. M. Scanlan, D. R. Dieterich, E. W. Collings, M. D. Sumption, L. R. Motowidlo,
Y. Aoki, and T. Hasegawa, "Bi:2212/Ag-based Rutherford cables: production,
processing, and properties," Supercond. Sci. and Tech., 12: 87-96, 1999.
M. D. Sumption, E. W. Collings, R. M. Scanlan, A. Nijhuis, H. H. J. ten Kate, S. W.
Kim, M. Wake, and T. Shintomi, "Influence of strand surface condition on
interstrand contact resistance and coupling loss in NbTi-wound Rutherford
cables," Cryogenics, 39: 197-208, 1999.
M. D. Sumption, E. W. Collings, R. M. Scanlan, A. Nijhuis, and H. H. J. ten Kate,
"Core-suppressed AC loss and strand-moderated contact resistance in a Nb3Sn
Rutherford cable," Cryogenics, 39: 1-12, 1999.
M. D. Sumption and E. W. Collings, "Low field flux jumping in high performance
multifilamentary Nb3Al and Nb3Sn composite strands," IEEE Trans. Appl.
Supercond., 9: 1455-1458, 1999.
F. Buta, M. D. Sumption, E. W. Collings, N. Harada, E. Gregory, and M. Tomsic,
"Short-sample quenching of Nb3Al precursor strand in support of reel-to-reel
process development," IEEE Trans. Appl. Supercond., 9: 1433-1436, 1999.
E. Gregory, M. Tomsic, F. Buta, M. D. Sumption, and E. W. Collings, "Process
development and microstructures of Nb3Al precursor strand for reel-to-reel
production," IEEE Trans. Appl. Supercond., 9: 2692-2695, 1999.
F. Sumiyoshi, S. Kawabata, T. Gohda, A. Kawagoe, T. Shintomi, E. W. Collings,
M. D. Sumption, and R. M. Scanlan, "AC losses in Nb3Sn Rutherford cables with a
stainless steel core," IEEE Trans. Appl. Supercond., 9: 731-734, 1999.
E. W. Collings, M. D. Sumption, R. M. Scanlan, D. R. Dietderich, L. R. Motowidlo,
R.S. Sokolowski, Y. Aoki, and T. Hasegawa, "Design, processing, and properties
of Bi:2212/Ag Rutherford cables," Advances in Superconductivity-XI, N.
Koshizuka and S. Tajima, eds. (Springer-Verlag Tokyo 1999) pp. 1369-1372.
M. D. Sumption and E. W. Collings, "Aspect ratio dependence of effective
transverse matrix resistivity in multifilamentary HTSC/Ag strands," Advances in
Superconductivity-XI, N. Koshizuka and S. Tajima, eds. (Springer-Verlag Tokyo
1999) pp. 831-834.
Published in 2000:
11.
F. Buta, M. D. Sumption, E. W. Collings, and M. Tomsic, "Progress in pilot-scale
production of high-temperature-processed Nb3Al strand," Adv. Cryo. Eng.
(Materials), 46: 1011-1043, 2000.
12.
13.
14.
15.
16.
M. D. Sumption, E. W. Collings, A. Nijhuis, and R. M. Scanlan, "Coupling current
control in stabrite-coated NbTi Rutherford cable by varying the width of a
stainless steel core," Adv. Cryo. Eng. (Materials), 46: 1043-1049, 2000.
M. D. Sumption, R. M. Scanlan, A. Nijhuis, and E. W. Collings, "AC loss and
contact resistance in copper-stabilized Nb3Al Rutherford cables with and without
a stainless steel core," IEEE Trans. Appl. Supercond., 10: 1196-1199, 2000.
E. W. Collings, E. Lee, and M. D. Sumption, "Magnetic measurements of AC loss
in short multifilamentary tapes," Advances in Superconductivity-XII, eds. T.
Yamashita, K. Tanabe (Springer-Verlag Tokyo 2000) pp. 709-714.
M. D. Sumption, E. Lee, and E. W. Collings, "Extraction of matrix resistivity from
short samples of superconducting multifilamentary composite tapes: influence of
strand twist and internal structure," Physica C, 335: 164-169, 2000.
M. D. Sumption, E. Lee, and E. W. Collings, "Influence of filamentary and strand
aspect ratios on AC loss in short untwisted samples of HTSC and LTSC
superconducting multifilamentary composites", Physica C, 337: 187-194, 2000.
Submitted in 2000:
17.
18.
19.
20.
21.
22.
23.
24.
E. W. Collings and M. D. Sumption, "Static and dynamic parasitic magnetizations
and their control in superconducting accelerator dipoles," The International
Cryogenic Materials Conference -- ICMC'2000: Superconductors for Applications,
Material Properties and Devices, June 11-15, 2000, Rio de Janeiro, Brazil, Physica
C -- submitted.
M. D. Sumption, R. M. Scanlan, and E. W. Collings, "Coupling loss and contact
resistance in cored stabrite cables -- influences of compaction and variation of
core width," IEEE Trans. Appl. Supercond. 11 -- submitted.
E. W. Collings, M. D. Sumption, and E. Lee, "Magnetization as a critical defining
parameter for strand in precision dipole applications -- implications for field error
and F-J stability," IEEE Trans. Appl. Supercond. 11 -- submitted.
M. D. Sumption, E. Lee, and E. W. Collings, "Analysis of eddy current AC loss for
untwisted, multifilamentary superconducting composites with various aspect
ratios," IEEE Trans. Appl. Supercond. 11 -- submitted.
N. Harada, T. Hamajima, F. Buta, E. Lee, M. D. Sumption, E. W. Collings, K.
Nakagawa, T. Takeuchi, H. Wada, and K. Watanabe, "Superconducting
properties in transformed jelly-roll Nb3Al multifilamentary wires with controlled
maximum temperature," IEEE Trans. Appl. Supercond. 11 -- submitted.
F. Buta, M.D. Sumption, and E.W. Collings, "Optimization studies for processing
Nb3Al using a rapid ohmic-heating and quenching method," IEEE Trans. Appl.
Supercond. 11 -- submitted.
J. Horvat, T. Hughes, S. Dou, E. W. Collings, and F. Darmann, "Transverse
resistivity in Bi2223/Ag tapes," IEEE Trans. Appl. Supercond. 11 -- submitted.
E. W. Collings and M. D. Sumption, "Transverse resistivities in untwisted HTSC
tapes at 4.2, 30, And 60 K," ISS'2000, 13th International Symposium on
Superconductivity, Tokyo, Japan, Oct. 14-16, 2000, Physica C -- submitted.
25.
26.
M. D. Sumption, E. W. Collings, R. M. Scanlan, S. W. Kim, M. Wake, T. Shintomi,
A. Nijhuis, and H. H. J. ten Kate, "AC Loss and interstrand contact resistance in
bare and coated NbTi/Cu Rutherford cables with cores," Supercond. Sci. and
Tech. -- submitted.
M. D. Sumption, E. W. Collings, R. M. Scanlan, S. W. Kim, M. Wake, T. Shintomi,
A. Nijhuis, and H. H. J. ten Kate, "AC loss in cored stabrite cables in response to
external compaction and variation of core thickness and width," Cryogenics -submitted.
Current Staff:
•
•
•
•
•
Collings, E.W.
Sumption, M.D.
Buta, F.
Lee, E.
Peng, X.
PI
Co-PI
Graduate Student
Graduate Student
Graduate Student
Edward W. Collings (PI) and Michael D. Sumption (Co-PI)
The Ohio State University
Department of Materials Science and Engineering
477 Watts Hall, 2041 College Rd
COLUMBUS, OH 43210
PHONE:
FAX:
E-MAIL:
Website:
614/688-3701 (EWC) and 614/688-3684 (MDS)
614/688-3677
[email protected] and [email protected]
http://www.mse.eng.ohio-state.edu/lasm/lasm.htm
Figure. 1. Experimental setup for rapid
ohmic heating-quenching processing of
short Nb3Al superconductor samples.
Figure. 2. Back-scattering SEM micrograph
of a cross-section in a Nb3 Al sample showing
partial melting that leads to a decreased
critical current density.
NC5000-3 FO
NC5000-3 EO
NC5000-5 FO
NC5000-5 EO
NC5000-7 FO
NC5000-7 EO
NC5000-9 FO
NC5000-9 EO
NC5000-13 FO
NC5000-13 EO
NC5000-14 FO
NC5000-14 EO
NC5000-1
20
4
5
Normalized eddy current loss, Q e /L (10 erg/cm ) FRV
25
2
15
Figure. 3. Vibrating Sample Magnetometer
used for magnetic properties and AC loss
measurements on superconducting strands.
10
5
0
-5
0
200
400
600
800
Ramp rate, dH/dt (Oe/s)
Figure. 4. Shape factor dependence of eddy
current loss for a 5000-filament NbTi strand
in face-on and edge-on magnetic field
orientations.
Nonlinear Dynamics and Collective Processes
in Intense Charged Particle Beams
R.C. Davidson – Princeton University
Summary:
A fundamental understanding of collective processes and nonlinear effects on the
propagation, acceleration, and compression of high-brightness, high-intensity charged
particle beams for high energy physics applications is essential to the identification of
optimum operating regimes in which emittance growth and beam losses are minimized.
Collective processes and space-charge effects become particularly important at the high
beam intensities and luminosities envisioned in present and next-generation
accelerators and transport systems. Under the auspice of the Department of Energy's
High Energy Physics Division, we have recently initiated a theoretical program in critical
problem areas related to the basic equilibrium, stability, and transport properties of
intense charged particle beams for high energy physics applications.
Particular emphasis is placed on kinetic investigations of collective processes and
nonlinear beam dynamics in parameter regimes for present and next-generation hadron
colliders and electron-positron colliders. The analysis makes use of advanced analytical
and numerical techniques to solve the nonlinear Vlasov-Maxwell equations, which
describe the self-consistent evolution of distribution function fb(x, p, t) in the
six-dimensional phase space (x, p) and the average electric magnetic fields, E (x, t)
and B (x, t), including both self-generated and applied (focusing) fields. The research
planned in this area includes: (a) determination of the sensitivity of the production of
energetic halo particles to beam intensity and luminosity, the amplitude of collective
excitations, and beam mismatch and bunch length in present and next-generation
hadron colliders and electron-positron colliders; (b) application of 3D multispecies
nonlinear perturbative simulation techniques to investigate detailed nonlinear processes
and collective interactions involving two charge components, with particular emphasis
on the electron cloud instability in high-energy hadron colliders, and beam-beam
interactions in electron-positron colliders; and (c) identification of operating conditions
for optimum performance (beam stability, luminosity, etc.). The theoretical
investigations will make extensive use of the analytical and numerical techniques
developed by the investigators to study the nonlinear dynamics and collective processes
in charged particle beams with intense self fields (see publications listed below).
Recent accomplishments in related research topics include: (a) development of a kinetic
(Vlasov-Maxwell) model for describing intense nonneutral beam propagation in periodic
focusing field configurations, including development of Hamiltonian averaging
techniques, and derivation of nonlinear kinetic stability theorem for quiescent beam
propagation over large distances; (b) application of a kinetic model to determine
detailed properties of the electron-ion two-stream instability when an electron
component is present in the acceleration region or transport lines; (c) application of a
test-particle model to explore chaotic particle dynamics and halo formation induced by
collective mode excitations in high-intensity beams; and (d) development of nonlinear
2D and 3D perturbative simulation schemes for intense beam propagation in periodic
focusing systems, including application to stable, matched-beam propagation over
hundreds of lattice periods, and detailed investigation of the nonlinear evolution of the
two-stream instability at high beam intensities.
Publications:
1. "Production of Halo Particles by Excitation of Collective Modes in High-Intensity
Charged Particle Beams," S. Strasburg and R. C. Davidson, Physical Review E61,
5753 (2000).
2. "Three-Dimensional Nonlinear Perturbative Particle Simulations of Collective
Interactions in Intense Particle Beams," H. Qin, R. C. Davidson and W. W. Lee,
Physics Letters A272, 389 (2000).
3. "Effects of Axial Momentum Spread on the Electron-Ion Two-stream Instability in
HighIntensity Ion Beams," R. C. Davidson and H. Qin, Physics Letters A270, 177
(2000).
4. "Warm-Fluid Stability Properties of Intense Nonneutral Charged Particle Beams with
Pressure Anisotropy," R. C. Davidson and S. Strasburg, Physics of Plasmas 7, 2657
(2000).
5. "A Paul Trap Configuration to Simulate Intense Nonneutral Beam Propagation Over
Large Distances Through a Periodic Focusing Quadrupole Magnetic Field," R. C.
Davidson, H. Qin, and G. Shvets, Physics of Plasmas 7, 1020 (2000).
6. "3D Nonlinear Perturbative Particle Simulations of Two-Stream Collective Processes
in Intense Particle Beams," H. Qin, R. C. Davidson and W. W. Lee, Physical Review
Special Topics on Accelerators and Beams 3, in press (2000).
7. "Single-Paxameter Characterization of the Thermal Equilibrium Density Profile for
Intense Nonneutral Charged Particle Beams," R. C. Davidson and H. Qin, Physical
Review Special Topics on Accelerators and Beams 2, 114401 (1999).
8. "Phase Space Structure for Intense Charged Particle Beams in Periodic Focusing
Transport Systems," C. Chen, R. Pakter, and R. C. Davidson, Physics of Plasmas 6,
3647 (1999).
9. "Periodically-Focused Solutions to the Nonlinear Vlasov-Maxwell Equations for
Intense Beam Propagation Through an Alternating-Gradient Field," R. C. Davidson,
H. Qin, and P. J. Channell, Physical Review Special Topics on Accelerators and
Beams 2, 074401 (1999); 3, 029901 (2000).
10. "Periodically-Focused Intense Beam Solutions to the Nonlinear Vlasov-Maxwell
Equations," R. C. Davidson, H. Qin, and P. J. Channell, Physics Letters A258, 297
(1999).
11. "Production of Halo Particles by Collective Mode Excitations in High-Intensity
Charged Particle Beams," S. Strasburg and R. C. Davidson, Proceedings of the 1999
Particle Accelerator Conference, pp. 1518-1520 (1999).
12. "Periodically-Focused Solutions to the Nonlinear Vlasov-Maxwell Equations for
Intense Beam Propagation Through an Alternating-Gradient Quadrupole Field," H.
Qin, R. C. Davidson, and P. J. Channell, Proceedings of the 1999 Particle Accelerator
Conference, pp. 1629-1631 (1999).
13. 2
14. "Kinetic Description of the Electron-Proton Instability in High-Intensity Linacs and
Storage Rings," R. C. Davidson, W. W. Lee, and T. -S. Wang, Proceedings of the
1999 Particle Accelerator Conference, pp. 1623-1625 (1999).
15. "Multispecies Nonlinear Perturbative Particle Simulation of Intense Charged Particle
Beams," H. Qin, R. C. Davidson, and W. W. Lee, Proceedings of the 1999 Particle
Accelerator Conference, pp. 1626-1628 (1999).
16. "Analysis of Phase Space Structure for Matched Intense Charged Particle Beams in
Periodic Focusing Transport Systems," C. Chen, R. Pakter, and R. C. Davidson,
Proceedings of the 1999 Particle Accelerator Conference, pp. 1875-1877 (1999).
17. "Kinetic Description of Electron-Proton Instability in High-Intensity Proton Linacs and
Storage Rings Based on the Vlasov-Maxwell Equations," R. C. Davidson, H. Qin, P. H.
Stoltz, and T. -S. Wang, Physical Review Special Topics on Accelerators and Beams
2, 054401 (1999).
18. "Vlasov-Maxwell Description of Electron-Ion Two-Stream Instability in High-Intensity
Linacs and Storage Rings," R. C. Davidson, H. Qin, and W. -S. Wang, Physics Letters
A252, 213 (1999).
19. "Nonlinear W Simulation Studies of High-Intensity Ion Beam Propagation in a
Periodic Focusing Field," P. H. Stoltz, R. C. Davidson, and W. W. Lee, Physics of
Plasmas 6, 298 (1999).
20. "Three-Dimensional Kinetic Stability Theorem for High-Intensity Charged Particle
Beams, R. C. Davidson, Physics of Plasmas 5, 3459 (1998).
21. "Warm-Fluid Description of Intense Beam Equilibrium and Electrostatic Stability
Properties," S. M. Lund and R. C. Davidson, Physics of Plasmas 5, 3028 (1998).
22. "Kinetic Stability Theorem for High-Intensity Charged Particle Beams Based on the
Nonlinear Vlasov-Maxwell Equations," R. C. Davidson, Physical Review Letters 81,
991 (1998).
23. "Kinetic Description of Intense Nonneutral Beam Propagation Through a Periodic
Solenoidal Focusing Field Based on the Nonlinear Vlasov-Maxwell Equations," R. C.
Davidson and C. Chen, Particle Accelerators 59, 175 (1998).
24. "Statistically-Averaged Rate Equations for Intense Nonneutral Beam Propagation
though a Periodic Solenoidal Focusing Field Based on the Nonlinear Vlasov-Maxwell
Equations," R. C. Davidson, W. W. Lee, and P. Stoltz, Physics of Plasmas 5, 279
(1998).
25. "Kinetic Description of Intense Nonneutral Beam Propagation Through a Periodic
Focusing Field," R. C. Davidson and Chiping Chen, Nuclear Instruments and Methods
in Physics Research A415, 370 (1998).
Figure 1: Illustrative plots of the electron-proton two-stream instability obtained
numerically using the Beam Equilibrium, Stability and Transport (BEST) code for a
high-intensity proton beam with OJ02b/2,yb2wO2_L = 0.074, -yb = 1.85, Tbl-YbmbVb2
= 3.61 x 10-r, f = klftb = 0.1, Te I Ab I = 0. 130. Plots show transverse projections of
the (a) equilibrium number density profiles of protons and electrons, and perturbed
space-charge potential 6OeZb/,ybMbVb2 at (b) t = 0 and (c) t = 2001wp-L . In (d), the
perturbed proton density amplitude is plotted versus w,O i t. Note the strong dipole
feature of the instability in (c), and the nonlinear saturation of the instability in (d).
Current Staff:
•
•
•
•
•
•
R. C. Davidson
W. Wei-li Lee
Hong Qin
Stephan Tzenov
Ronald Stowell
Sean Strasburg
Graduate Student
Graduate Student
Ronald C. Davidson (PI)
Princeton University
PPPL
PO Box 451
Princeton, New Jersey
PHONE: 609/243-3553
FAX: 609/243-2749
Advanced Accelerator Studies
Summary:
N. Fisch and G. Shvets – Princeton University
Our theoretical/computational group, consisting of Drs. N. J. Fisch and G. Shvets, and a
Ph.D. student X. Li, is pursuing several topics in laser-plasma interactions of relevance
to the development of advanced plasma-based accelerators. Significant progress has
been made in three areas: (i) generation of high-gradient periodic accelerating
structures in the plasma using counter-propagating laser beams, (ii) plasma wave
generation and laser propagation in plasma channels, and (iii) novel radiation sources
which utilize lasers and plasmas.
Colliding Beam Accelerator
We have developed a new approach to generating accelerating wakes in plasma, which
does not require ultra-high intensity lasers, yet produces plasma wakes of interest to
high-energy physics (Eo > 1 GeV/m). This scheme, Colliding Beam Accelerator (CBA),
utilizes two counter-propagating laser beams of sub-relativistic intensities: a short
timing beam (TB) and a long pumping beam (PB). CBA is a radical departure from the
more traditional laser wakefield accelerator (LWFA) which utilizes a single short laser
pulse of ultra-high intensity I0 ~ 1018 W/cm2 . The addition of the second
counter-propagating laser beam significantly decreases the required intensity of the
short pulse while ensuring the high accelerating gradient (up to 10 GeV/m according to
our analytic calculations and the first-principles particle-in-cell simulations).
It turns out that the phase of this novel plasma wake is controlled by the frequency of
the pumping beam. Using particle simulations, we have demonstrated that by splitting
the pumping beam into separate variable-frequency pulses with gaps between them, a
periodic accelerating structure can be produced in the plasma. It consists of the
enhanced wake regions of controllable phase, separated by the gaps with negligible
wake. Independent phase control of each accelerating cavity is a given in conventional
accelerators. CBA enables us to achieve the same in a laser-plasma accelerator.
Laser propagation and wake excitation in plasma channels
To ensure long acceleration distance, plasma channels will be employed in the future
laser-plasma accelerators to achieve the guiding of the laser pulses uninhibited by
diffraction. Therefore, it is important to quantitatively understand the plasma wake
excitation in a channel. Unlike the indefinitely persisting fixed frequency plasma wakes
in the homogeneous plasma, the "quasi-modes" of the plasma channel decay due to the
phase-mixing of plasma oscillations with spatially-varying frequencies. We derived the
Q-factor of the plasma wake in a channel and demonstrated that a longer than λp/4
overlap between the focusing and accelerating sections of the wake exists in plasma
channels. We are also investigating stimulated Raman scattering in the channel.
Laser-driven undulator radiation
Another application of the intense laser-plasma interactions is generation of tunable
high-power radiation at frequencies unavailable from the conventional sources. We
proposed a novel method of producing the laser-driven undulator radiation in the
infrared (LURI) which utilizes a short laser pulse, magnetic undulator, and tenuous
plasma. The principle of LURI can be understood by noting that a short laser pulse
propagating through the periodically magnetized plasma produces a local current
disturbance in the plasma that acts as a "virtual" electron beam. In this respect, the
LURI source is similar to the conventional beam-driven source of the undulator
radiation, except that there is no beam! The frequency of the LURI, determined by the
plasma density and the undulator period, is easily tunable.
A beatwave of two co-propagating laser pulses, detuned by the LURI frequency, can be
utilized instead of the short laser pulse. This process is best described as the
quasi-phasematched difference frequency generation in the plasma. Periodic magnetic
field serves two purposes: (a) removes the inversion symmetry of the plasma which
forbids the sum and difference frequency generation due to the vanishing χ2 coefficient,
and (b) secures the quasi-phasematching of the process. Thus produced radiation can
be used for developing an injector into a plasma beatwave accelerator.
Summary of the current staff
The following scientific personnel is currently involved in the advanced accelerator
research funded by the Advanced Technology R&D subprogram of the Division of High
Energy Physics:
•
•
•
Dr. Nathaniel J. Fisch
Dr. Gennady Shvets
Mr. Xiaohu Li
Co-Principal Investigator
Ph.D. candidate
Mr. Li is in his sixth year in graduate school, he has been working with Gennady Shvets
for the past three years. His research concentrated on the theory and simulations of the
plasma wave excitation in plasma channels, parametric Raman instabilities of intense
lasers in plasma channels, and the Hamiltonian formulation of the dynamics of the
electron oscillation centers in the ultra-intense laser field. Mr. Li is expected to graduate
some time this fall from Princeton University with a Ph.D. degree in Astrophysical
Sciences. His support came primarily from the Theory Department of PPPL. Additional
support for attending conferences and publications costs came from the funding by the
Division of High Energy Physics.
Gennady Shvets (PI)
Princeton University
PO Box 451
Princeton, New Jersey 08543
The Laser Electron Accelerator Project at Stanford University
R.L. Byer - Stanford University
Summary:
Description:
The goal of the laser driven electron accelerator program (LEAP) is to demonstrate laser
acceleration in vacuum experimentally. LEAP is a joint project with the participation of
SLAC, the Hansen Experimental Physics Laboratory (HEPL) and the Department of
Applied Physics.
The laser accelerator cell consists of a glass structure with reflective surfaces arranged
in a geometry such that a pair of crossed gaussian laser beams interacts with a
relativistic electron beam for a distance of ~ 1mm. The phase-slippage between the
laser beam and the electron beam does not allow for longer interaction distances. A
thin slit, that cannot be wider than 10 µm, is provided in the glass structure to prevent
the electron beam from traveling in glass. A 32 MeV, ultra low energy spread electron
beam is provided and the laser beam is generated by a regeneratively amplified
Ti:Sapphire laser with a wavelength of 800 nm and a pulse duration of ~1 to 10 psec.
See Figure 1.
An energy spectrometer located 1/2 m behind the accelerator cell is employed to record
the energy spectrum of each electron beam. The spectrometer has a resolution of P/δP
of 10000, thus capable of revealing 2 keV features. We expect to cause a laser induced
effect of a few tens of keV that will manifest itself as an energy broadening of the
energy spectrum of the electron beam. See Figure 2.
In the three years of funding for this project the following milestones have been
accomplished:
•
•
•
•
•
Characterization of single electron beam bunches at the energy spectrometer
Successful transport of the laser beam to the accelerator cell
Transmission of the electron beam through a 10 µm accelerator cell slit
Temporal overlap of the laser and electron beam to within 100 psec as observed
with the aid of a streak camera.
Spatial overlap of the electron beam and the laser beam to within 100 µm.
The preparations for the next accelerator run are the following
•
Due to the excessive laser power employed the laser accelerator cell was
damaged during the previous run. In order to prevent laser-damage careful
measurements of the damage threshold of the material in vacuum are being
performed.
•
•
In addition a 1-D camera will replace a gated video camera at the energy
spectrometer. This will allow to capture energy profiles at higher repetition rates.
Finally, the trigger electronics for the streak camera responsible for monitoring
the temporal overlap of the electron beam and the laser beam is being modified
in order to improve the present temporal resolution of 100 psec
The preparations for the next accelerator run are the following:
•
•
•
Due to the excessive laser power employed the laser accelerator cell was
damaged during the previous run. In order to prevent laser-damage careful
measurements of the damage threshold of the material in vacuum are being
performed.
In addition a 1-D camera will replace a gated video camera at the energy
spectrometer. This will allow capturing energy profiles at higher repetition rates.
Finally, the trigger electronics for the streak camera responsible for monitoring
the temporal overlap of the electron beam and the laser beam is being modified
in order to improve the present temporal resolution of 100 psec
Publications:
1. T. Plettner, J.E. spencer, Y.C. Huang, R.L. Byer, R.H. Siemann, and T.I. Smith, “The
Laser Driven Particle Accelerator Project: Theory and Experiment,” in AIP
Proceedings on Advanced Accelerator Concepts, vol. 472, Wes Lawson, Carol
Bellamy, and Dorothea F. Brosius, eds. (American Institute of Physics, New York,
1999), pp. 118-127.
2. Y.C. Huang, Y.W. Lee, T. Plettner, and R.L. Byer, “The Proposed InterferometricType Laser-Driven Particle Accelerators,” in AIP Proceedings on Advanced
Accelerator Concepts, vol. 472, Wes Lawson, Carol Bellamy, and Dorothea F.
Brosius, eds. (American Institute of Physics, New York, 1999), pp. 581-591.
Invited Talks and Seminars
1. T. Plettner (for R.L. Byer), “The Laser Electron Accelerator Project:Theory and
Experiment,” 8th Workshop of Advanced Accelerator Concepts, Baltimore, Maryland
(July 5-11, 1998)
2. T. Plettner, “Progress of the laser driven electron accelerator experiment at Stanford
University”, PAC’99, New York (March 29 - April 2, 1999)
Patent Application
•
1997 Yen-Chieh Huang and Robert L. Byer, “Dielectric Based Crossed Laser Driven
Vacuum Laser Particle Accelerator” [S97-043]
The patent application proposed the laser driven particle accelerator concept
based on a dielectrc accelerator structure. Experiments are in progress to
demonstrate the invention.
Current Staff:
•
•
•
•
•
•
•
•
•
Byer, R.L.
Siemann, R.H.
Spencer, J.
Smith, T.I.
Swent, R.L.
Colby, E.
Plettner, T.
Cowan, B.
Barnes, C.
.
PI
Co-PI
Senior Staff
Senior Staff
Senior Staff
Postdoc
Graduate Student
Graduate Student
Graduate Student
Robert L. Byer (PI) and Robert H. Siemann (CoPI)
Stanford University
Department of Applied Physics
STANFORD CA 94305 - 4085
PHONE:
FAX:
E-MAIL:
Website:
650/723-0226
650/723-2666
[email protected]
http://www.stanford.edu/~rlbyer/
Figure 1: The laser-accelerator cell
crossed
laser beams
slit
slit
crossed
laser beams
slit
e-beam
e-beam
diagonal
high - reflector
coated surface
normal
high - reflector
coated surface
Schematic diagram
laser beam
electron
beam
e-beam
e-beam
Perspective view
side view
Figure 2: Observed energy profiles and expected energy profile from laser-driven
acceleration.
Simulation of the energy spectrum
Observed sequence of energy profiles
image number
Tlaser=5 psec, Telectr on=1 psec, ∆slit =10 µm
-40 keV
Energy (keV)
+40 keV
200
laser on
0
laser off
400
600
1
2
3
4
5
Staged Electron Laser Acceleration (STELLA) Experiment
W.D. Kimura – STI Optronics, Inc.
Summary:
Future electron accelerators require much higher acceleration gradients than presently
available using microwave sources. Applications include elementary particle research,
and compact accelerators for medical, biological, materials research, and industrial
applications. Laser accelerators have demonstrated acceleration gradients over 1,000
times greater than microwave accelerators. However, this has been limited to distances
of <1 mm to several millimeters. Achieving high net energy gain requires staging the
laser acceleration process, whereby the electrons interact repeatedly with the laser
beam, and are guided and accelerated in an organized fashion through multiple laser
acceleration stages. Up until now no one has demonstrated that such staging is
possible in laser accelerators.
We have demonstrated this staging process for the first time in a proof-of-principle
experiment called Staged Electron Laser Acceleration (STELLA) located at the
Brookhaven National Laboratory (BNL) Accelerator Test Facility (ATF). The lead
institution for this effort is STI Optronics, Inc. (STI), a small business located in
Bellevue, Washington, and is in collaboration with BNL, UCLA, and Stanford University.
During the experiment, an inverse free electron laser (IFEL) served as the prebuncher
and a second IFEL positioned 2.3 m downstream from the prebuncher served as the
accelerator. Both IFELs used identical permanent-magnet arrays, called undulators,
designed and built by STI. The ATF CO2 laser is split into two beams and sent to the
IFELs. An adjustable optical delay stage is used in the laser beam transport line to the
second IFEL to adjust the laser beam phase with respect to the electron microbunches
produced by the prebuncher. These microbunches consist of a train of ~1-µm long
bunches separated by the laser wavelength (10.6 µm).
The noteworthy accomplishments of the STELLA program are: 1) The first
demonstration of a laser-driven prebuncher staged together with a laser-driven
accelerator; 2) the first direct measurement of ~2-fs microbunches produced by a laser
driving an undulator; 3) the first demonstration of acceleration of laser-generated
microbunches with stable phase control maintained over periods of many minutes; and
4) the first demonstration of laser accelerated microbunches where a large portion of
the electrons receive maximum energy gain. This last achievement is noteworthy
because laser acceleration experiments to date typically have only a relatively small
number of electrons experiencing a narrow energy gain.
Future work will utilize the higher power that will be available from the ATF CO2 laser in
order to demonstrate monoenergetic laser acceleration, whereby a clear separation of
the accelerated microbunch electrons from the nonaccelerated ones is achieved
together with a narrow energy spread (~1%).
In parallel with the experimental part of the STELLA program has been on-going
theoretical work on advanced laser acceleration concepts and issues. This includes new
approaches for laser acceleration in free space (i.e., vacuum laser acceleration) and
analysis of space charge effects in laser accelerators.
Publications: (1999 – August 2000)
1.
2.
3.
4.
5.
6.
7.
8.
9.
W. D. Kimura, et al., “STELLA Experiment: Design and Model Predictions,” in
Advanced Accelerator Concepts, Baltimore, MD, AIP Conference Proceedings No.
472, W. Lawson, C. Bellamy, and D. Brosius, Eds., (American Institute of Physics,
New York, 1999), p. 563-572.
K. P. Kusche, et al., “STELLA Experiment: Hardware Issues,” in Advanced
Accelerator Concepts, Baltimore, MD, AIP Conference Proceedings No. 472, W.
Lawson, C. Bellamy, and D. Brosius, Eds., (American Institute of Physics, New
York, 1999), p. 573-580.
L. C. Steinhauer and W. D. Kimura, “Space Charge Compensation in Laser Particle
Accelerators,” in Advanced Accelerator Concepts, Baltimore, MD, AIP Conference
Proceedings No. 472, W. Lawson, C. Bellamy, and D. Brosius, Eds., (American
Institute of Physics, New York, 1999), p. 599-608.
R. B. Fiorito, et al., “Noninvasive Beam Position, Size, Divergence, and Energy
Diagnostics Using Diffraction Radiation,” in Advanced Accelerator Concepts,
Baltimore, MD, AIP Conference Proceedings No. 472, W. Lawson, C. Bellamy, and
D. Brosius, Eds., (American Institute of Physics, New York, 1999), p. 725-734.
D. W. Rule, et al., “The Effect of Detector Bandwidth on Microbunch Length
Measurements Made With Coherent Transition Radiation,” in Advanced
Accelerator Concepts, Baltimore, MD, AIP Conference Proceedings No. 472, W.
Lawson, C. Bellamy, and D. Brosius, Eds., (American Institute of Physics, New
York, 1999), p. 745-754.
L. C. Steinhauer and W. D. Kimura, “Longitudinal Space Charge Debunching and
Compensation in High Frequency Accelerators,” Phys. Rev. ST Accel. Beams 2,
081301 (1999).
L. P. Campbell, et al., “Inverse Cerenkov Acceleration and Inverse Free Electron
Laser Experimental Results for Staged Electron Laser Acceleration,” to be
published in IEEE Transactions on Plasma Science Special Issue on Second
Generation Plasma and Laser Accelerators.
M. Babzien, et al., “Demonstration of a Laser-Driven Prebuncher Staged With a
Laser Accelerator - The STELLA Program,” to be published in Advanced
Accelerator Concepts, Santa Fe, NM.
L. C. Steinhauer, “Direct Laser Acceleration in a Capillary Channel,” to be
published in Advanced Accelerator Concepts, Santa Fe, NM.
2
10.
W. D. Kimura, et al., “First Staging of Two Laser Accelerators,” submitted for
publication in Physical Review Letters.
Current Staff:
•
•
•
•
•
•
Kimura, Wayne D.
Quimby, David C.
Gottschalk, Stephen C.
Campbell, Lora P.
Dilley, Christian E.
Steinhauer, Loren C.
PI
FEL/IFEL theory and modeling
Undulator design and modeling
Technician support
Technician support
Laser acceleration theory
Dr. Wayne D. Kimura (PI)
STI Optronics, Inc.
2755 Northup Way
Bellevue, WA 98004-1495
PHONE:
FAX:
E-MAIL:
Website:
425/827-0460, ext. 312
425/828-3517
[email protected]
www.stioptronics.com
3
CO2 LASER BEAM
ADJUSTABLE
OPTICAL
DELAY
STAGE
FOCUSING LENSES
DIPOLE
MAGNET
PREBUNCHER
(IFEL1)
ACCELERATOR
(IFEL2)
SPECTROMETER
VIDEO CAMERA
WIGGLER
MAGNET
ARRAY
E-BEAM
FOCUSING
LENSES
E-BEAM
FOCUSING
LENSES
VACUUM
PIPE
MIRROR WITH
CENTRAL HOLE
WIGGLER
MAGNET
ARRAY
E-BEAM
Photograph of wiggler
used for IFELs shown in its
raised position off of the
beamline.
= QUADRUPOLE MAGNET
MIRROR WITH
CENTRAL HOLE
Schematic of STELLA experiment.
Direction of Increasing Energy ⇒
(a) Laser off to both IFELs.
Signal
strength increases from violet, blue,
green, yellow, to red.
White is
saturation.
(b) Lasers on to both IFELs. Near-optimal
modulation in prebuncher (IFEL1) results in acceleration of the microbunches at the proper phase delay
(c) Same conditions as (b) with phase
delay set 180° from (b). At this phase
delay
the
microbunches
are
decelerated.
Raw video images from electron energy spectrometer.
0
1
2
3
4
5
Model
Data
200
100
0
-2
-1
0
1
Energy Shift (MeV)
(a)
2
Number of Electrons
300
Energy Shift (MeV)
Electron Distribution
Energy Shift (%)
-5 -4 -3 -2 -1
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
400
300
200
100
0
-3
-2
-1
0
1
Output Phase (rad)
(b)
2
3
-5 -4 -3 -2 -1
0
1
2
3
4
5
Electron Bunch Length (µ
µm)
(c)
Comparison between model and data for phase delay corresponding to maximum
acceleration. (a) Electron energy spectrum. The corresponding phase-space and
microbunch length predictions are given in (b) and (c), respectively.
4
High-field Superconducting Magnet R&D at Texas A&M University
Peter McIntyre and Al McInturff-TAMU
Summary:
The accelerator research group at Texas A&M University is developing dipole technology
for use in future hadron colliders. During the past several years, the group has
pioneered several innovations in magnet design, with the objective of achieving 12-16
Tesla in a manufacturable dipole:
the use of rectangular pancake coils,
stress management and shear release within the coil assembly, and
stabilization of the superconductor using pure copper strands within the cables.
While each of these elements has been used in one form or another in the past for
other applications, the Texas group has combined them to particular advantage to
control stress within the fragile Nb3Sn coils of a high-field dipole and to dramatically
reduce the amount of superconductor needed to achieve a given field strength.
The control of stress is vital for dipoles of 12 Tesla and beyond where the Lorentz
forces push the limit for destruction of insulating materials and damage of the fragile
Nb3Sn conductor. The Texas A&M design integrates a support matrix within the coil to
intercept Lorentz stress midway through the coil thickness and bypass it so that it
cannot accumulate to crushing levels in the outer windings.
The conventional approach to quench stabilization, in which stabilizing copper is simply
drawn into the superconducting strand, is a needless extravagance (one then pays
$800/kg for copper, instead of $10/kg!) The Texas group is developing a Rutherford
cable in which much of the stabilizing copper is provided as pure-Cu strands that are ca
bled along with the superconducting strands.
The Texas group has proposed the possibility of a Tevatron Tripler. The single ring of 4
Tesla NbTi dipoles in the Fermilab Tevatron could be replaced by a ring of 12 Tesla
Nb3Sn dipoles. The upgraded collider could use the same tunnel, injectors, p source,
and detectors. A collaboration of high energy phenomenologists has analyzed the
physics potential of such a high-luminosity pp collider at s = 6 TeV . They found that,
because of the valence antiquark content of the antiproton, the reach for the Higgs
boson and supersymmetry is nearly as great as that of LHC, and signatures for new
particles proceed through a significantly distinct group of parton-level processes.
During the past year the group has completed the construction of a first learning model
of the new dipole technology. The 7 Tesla learning model was built with NbTi (SSC
inner) cable, and embodies all of the features of pancake coil geometry and stress
management. It was built to evaluate and perfect the construction techniques needed
for the structure, prior to building a first high-field model using (expensive) Nb3Sn
conductor. It will be tested during the coming month.
After the experiences from building its first model magnet the group has prepared a
design for a first 12 Tesla Nb3Sn model dipole. The new dipole will incorporate two
additional innovations that have been made by the LBL group in their development of
the common-coil dipole: self-contained pancake coil subassemblies that eliminate the
need for external control of axial loading, and expandable bladders to deliver preload to
the coil assembly and relax dimensional tolerances. The group plans to build and test a
model dipole of this design during the coming year.
In a related development, the group has built a structured cable that enables the use of
the high-temperature superconductor Bi-2212 in practical coils. The cable is a 6-on-1
structure, in which the center element is a hollow spring tube, and an outer Inconel
jacket is drawn onto the cable to provide protection and manifolding of gas flow for
reaction bake and later for refrigeration during operation. Using currently available Bi2212 round strand a 3 mm diameter cable is capable of carrying 3,000 Amps at
arbitrarily high field strength!
12 Tesla Nb3Sn dipole assembly
7 Tesla NbTi model dipole
The group has successfully built the cable and demonstrated that its performance is not
degraded even by tight bends (1.5 cm radius). The hollow spring tube provides stress
management so that the cable should be capable of operation without degradation
even in thick coils. The hollow design also makes it possible to provide refrigeration in
a closed-circuit cryocooler rather than a pool-boiling
cryostat, opening the potential for a variety of
practical coil applications.
Bi-2212 structured cable cross-section
6-on-1 cabling operation
Publications 1999-2000
1.
2.
3.
4.
5.
6.
7.
8.
P. McIntyre, R. Soika et al, “A strain-tolerant Bi-2212 cable.” submitted to IEEE
Transactions on Applied Superconductivity, 1999
R. Blackburn et al., “12 Tesla hybrid block-coil dipole for future hadron colliders.”
submitted to IEEE Transactions on Applied Superconductivity.
M. Yavuz et al., “Solid solubility limit of Bi-Pb-Sr-Ca-Mn-O in Bi-Pb-Sr-Ca-Cu-O
superconductors,” submitted to IEEE Transactions on Applied Superconductivity.
V. Krutelyov et al., “Prospect for searches for gluinos and squarks at a Tevatron
Tripler” submitted to Phys. Lett. B (2000).
P. M. McIntyre, M. Yavuz, R. Soika, D. Naugle, and H. Faqu, “Effect of V doping
in Bi-Pb-Sr-Ca-Cu-O superconductor composites,” Physica C: Superconductivity
341-348, pp. 661-662 (2000).
N. Diaczenko et al., “Strain-tolerant cable using Bi-2212 superconductor” Physica
C: Superconductivity 341-348, pp. 2551-2554 (2000).
C. Battle, et al., “Optimized block-coil dipoles for future hadron colliders,” IEEE
Transactions on Applied Superconductivity, Vol. 10, pp. 334-337, 1999.
P. M. McIntyre, et al., “Strain-tolerant cable using Bi-2212 superconductor,” IEEE
Transactions on Applied Superconductivity, Vol. 10, pp. 1142-1145. Battle et al.,
“Optimization of block-coil dipoles for hadron colliders.” Proc. Particle Accelerator
Conf., New York, NY, March 30-April 1, 1999.
Laser Wakefield Acceleration research
T. Tajima – University of Texas
Summary:
Experimental research
Guiding of high intensity laser pulse
We achieved guiding of intense (I =1.3+/- 0.7 x 1017 W/cm2) 80 fs laser pulses with
negligible spectral distortion through 1.5 cm-long preformed helium plasma channels.
Channels were formed by axicon-focused Nd:YAG laser pulses of either 0.3 J energy, 100
ps duration, after pre-ionizing a 200-700 Torr backfill of He gas to ne ~ 1016cm-3 with a
pulsed electrical discharge; or 0.6-1.1 J energy, 400 ps duration, which required neither
pre-ionization nor intentional impurities for seeding. Transverse interferometry showed that
He was fully ionized on the channel axis in both cases. Identical fs pulses suffered
substantial ionization-induced blueshifts after propagating through Ar and Ne channels of
similar dimensions. Various weak probe pulses have been co-propagated with the main
pulse to investigate remaining ionization distortions and to probe for wakefields.
Optical probing of resonant laser wakefields
A collaboration initiated in 1998 uses the FALCON Laser/Linac facility LLNL that should
provide access to a 30 fs laser to be operating at 20 -100 TW. The goal of this project is to
generate and optically probe a Quasi 1D resonant laser Wakefield acceleration structure
during phase I, and eventually to attempt electron injection and acceleration as part of
phase II. Due to energy constraints in most laser systems, a tightly focussing geometry is
usually employed to achieve the high intensities, resulting in short interaction lengths and
wakefields with significant radial structure (2D regime). 1D Wakefields, (i.e. those in which
radial effects are negligible), are far superior in applicability to next-generation particle
acceleration schemes because of their low emittence properties. They are also
theoretically simpler, allowing comparison between experimental results and theoretical
models. Wakefields in this regime are the least studied, however, because the required
laser must satisfy the rather severe criteria of producing high peak intensity (I ~ 1017 - 1018
W/cm2) in a loose-focus geometry (spot size of ~50 – 100 microns, Rayleigh range of ~ 2 3 mm). The above parameters are not at UT and the goal of this collaboration is to
combine our expertise in wakefield generation and diagnosis, which has been
demonstrated at UT, with the unique laser and linac resources of the FALCON facility,
providing thus a unique opportunity to study and advance laser wakefield acceleration in
the usually inaccessible 1D regime.
Theoretical Investigations
Application of Laser Wakefield Accelerator to a High Energy Linear Collider
We continue our theoretical and computational studies of feasibility of a several TeV
electron-positron linear collider based on LWFA units. Taking into account general
requirements of the Interaction Point (IP) physics we consider several accelerator
scenarios. Identifying as crucial beam emittance preservation we study beam transport in
such a system using multistage map approach. Detailed study of the map properties helps
us to optimize in the multidimensional parameter space of the collider. As a result we
developed several mitigated focusing designs, namely channeled accelerator, superunit
design, and the “horn model”. We also started investigations of different feedback methods
as a way to preserve and control the emittance in the accelerator system. Including spin
degrees of freedom in our systems code allowed to consider transport of polarized beams,
which provides strong noise suppression at IP.
PIC simulations of ion acceleration and photon acceleration
We consider possibilities for ion acceleration. One-dimensional PIC simulations on ion
pickup and acceleration based on laser induced strongly nonlinear compressional Alfven
waves are performed.
Studies of laser pulse shape optimization and laser pulse collisions are in progress.
Recent Publications
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
E. W. Gaul, S. P. Le Blanc, and M. C. Downer, Technical Digest. Summaries of Papers
Presented at the International Quantum Electronics Conference. Conference Edition.
1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236). Opt. Soc. America.
1998, 40.
E. W. Gaul, S. P. Le Blanc, H. Langhoff, et al., Technical Digest. Summaries of papers
presented at the Conference on Lasers and Electro-Optics. Postconference Edition.
CLEO '99. Conference on Lasers and Electro-Optics (IEEE Cat. No.99CH37013). Opt.
Soc. America. 1999, 213.
S. P. Le Blanc, E. W. Gaul, and M. C. Downer, Technical Digest. Summaries of papers
presented at the Conference on Lasers and Electro-Optics. Postconference Edition.
CLEO '99. Conference on Lasers and Electro-Optics (IEEE Cat. No.99CH37013). Opt.
Soc. America. 1999, 535.
S. P. Le Blanc, E. W. Gaul, and M. C. Downer, Technical Digest. Summaries of Papers
Presented at the Conference on Lasers and Electro-Optics. Conference Edition. 1998
Technical Digest Series, Vol.6 (IEEE Cat. No.98CH36178). Opt. Soc. America. 1998,
280.
C. M. Fauser, E. W. Gaul, S. P. Le Blanc, et al., Applied Physics Letters 73, 2902
(1998).
H. Hojo, B. Rau, and T. Tajima, Elsevier. Nuclear Instruments & Methods in Physics
Research Section A-Accelerators Spectrometers Detectors & Associated Equipment
410, 509 (1998).
J. Koga, S. Kato, Y. Kishimoto, et al., Elsevier. Nuclear Instruments & Methods in
Physics Research Section A-Accelerators Spectrometers Detectors & Associated
Equipment 410, 499 (1998).
B. Rau and T. Tajima, Physics of Plasmas 5, 3575 (1998).
T. Tajima and P. Chen, Elsevier. Nuclear Instruments & Methods in Physics Research
Section A-Accelerators Spectrometers Detectors & Associated Equipment 410, 344
(1998).
P. Chen and T. Tajima, Physical Review Letters 83, 256 (1999).
S. Cheshkov, T. Tajima, W. Horton, et al., AIP. American Institute of Physics
Conference Proceedings, 343 (1999).
E. W. Gaul, S. P. Le Blanc, and M. C. Downer, AIP. American Institute of Physics
S. P. Le Blanc, E. W. Gaul, and M. C. Downer, AIP. American Institute of Physics
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
T. Tajima, S. Cheshkov, W. Horton, et al., AIP. American Institute of Physics
L. N. Tsintsadze, K. Nishikawa, T. Tajima, et al., Physical Review E. Statistical
Physics, Plasmas, Fluids, & Related Interdisciplinary Topics 60, 7435 (1999).
A. G. Zhidkov, A. Sasaki, T. Tajima, et al., Physical Review E. Statistical Physics,
Plasmas, Fluids, & Related Interdisciplinary Topics 60, 3273 (1999).
N. E. Andreev, M. V. Chegotov, M. C. Downer, et al., accepted at IEEE Transactions
on Plasma Science, August (2000).
S. Cheshkov and T. Tajima, J. Mod. Phys. A15, 2555 (2000).
E. W. Gaul, S. P. LeBlanc, A. Rundquist, et al., submitted to Applied Physics Letters,
(2000).
E. W. Gaul, N. E. Andreev, M. V. Chegotov, et al., Proceedings of the International
Conference on LASERS'99. Soc. Opt. & Quantum Electron. 2000, 281 (2000).
S. P. Le Blanc, E. W. Gaul, N. H. Matlis, et al., Optics Letters 25, 764 (2000).
A. Zhidkov, A. Sasaki, and T. Tajima, Physical Review E. Statistical Physics, Plasmas,
Fluids, & Related Interdisciplinary Topics 61, R2224 (2000).
A. Zhidkov, A. Sasaki, and T. Tajima, AIP. Review of Scientific Instruments 71, 931
(2000).
S. Cheshkov, T. Tajima, W. Horton, et al Physical Review ST-AB 3, 071301 (2000).
C. Chiu, S. Cheshkov, and T. Tajima, accepted to Physical Review ST-AB (2000).
Current Personnel
• T. Tajima (PI),
• M.C. Downer (PI),
Graduate students:
• E.W. Gaul,
• S. Cheshkov,
• N.H. Matlis,
• R Zgadzaj,
• F. Grigsby,
• T. Pfeiffer,
• M.Fomitsky
UT Austin – Helium plasma channels and diagnostic
Ti:S probe
Ti:S
YAG
axicon
∆T2
CCD1
∆T1
Reference
750 Torr He
He unchanneled
spectral intensity (arb.u.)
Spectrometer
E. W. Gaul, N. H. Matlis, R. Zgadzaj, and M. C. Downer
No spectral distortion in Helium!
780
790
800
810
820
nm
CCD2
Mode images of guided pulse
Interferogram
Distance propagated in channel:
6 mm 8 mm 10 mm 12 mm
Abel
inversion
guided peak intensity:
2 x 1017 W/cm2
Setup of UT guiding experiment, YAG pulse forms plasma channel, which is transversely probed by a weak
Ti:S pulse to get the electron density profile (b). A high intensity Ti:S pulse is guided along the channel. Its
spectrum is analyzed after the channel to measure distortions (c) and its spatial profile is recorded.
UT Austin -- LLNL Wakefield Collaboration
N. H. Matlis, S. P. Le Blanc, E. W. Gaul, A. Rundquist and M. C. Downer, T. Ditmire, T. Cowan
Falcon Laser
1D Wakefield
He
Pump
10 TW, 30 fs
λ=800 nm
Optical Diagnostics
ao= 0.5
λp=24 µm
2ro=50 µm
Photon acceleration,
Freq.Domain Hologr.
3 mm
•pre-ionized He
plasma
•Ez=17 GeV/m
Setup for UT-LLNL collaboration. Potential to achieve first laboratory 1D
Wakefield: study Wakefield lifetime, pump depletion, beam loading. Linac
available for electron acceleration
FDH setup
UT Austin – Ultrafast wakefield diagnostics
S. P. Le Blanc, E. W. Gaul, N. H. Matlis A. Rundquist and M. C. Downer
50 fs
Time Domain Frequency Domain
a) pump
b)
ωo
probe 2
pump
Langmuir waves/wakefield
φ(r,t)
shift of centroid
∆ω/ω > 10-3
t
Ionization front
r
Frequency Domain
Interferometry
• shift of interference
fringes
• ∆ω/ω < 10-2
pump
d) probe 1
probe
Photon Acceleration
pump probe
•
•
c)
reference 1 ps
Coherent Thomson Scattering
• sidebands shifted by ωp
• course time resolution
probe
probe 1
pump
LeBlanc et al Opt. Lett 25, p764 (2000)
data of ionization front
4r
120 Torr
helium
Frequency Domain
Holography
•
•
500
shift of interference fringes
∆ω/ω < 10-2
15
t(fs)
r(µm)
-15
-500
Various optical diagnostics for wakefield acceleration. Frequency domain interferometry and holography
were developed and demonstrated at UT Austin.
Emittance degradation in a 5 TeV linear collider
Active control of LWFA
Cheshkov et al., Phys. Rev. ST-AB 3, 071301 (2000).
presented at AAC 2000
a. The normalized x-emittance vs stage number
Emittance
−6
10
Stage Misplacement
−6
x 10
strong focus
4
5
emittance [m]
εx(m)
6
−8
10
weak focus
3
misplaced=4.519e−006m
corrected=8.807e−009m
4
position [µm]
−7
10
3
2
1
−9
10
500
N
0
−2
1000
2
2
20
4
10
time
15
6
10
8
c. Strong focusing
20
4
15
6
b. Weak focusing
1
−1
0
0
2
10
time
stage no
Emittance
50
50
10
8
5
5
stage no
Stage Misplacement
−6
x 10
1.5
1
0
position [µm]
emittance [m]
0
x
0
px/σp
0
px/σp
x
misplaced=1.32e−006m
corrected=2.844e−008m
1
0.5
0
−50
−20
0
0
x/σx
20
−50
−20
20
The normalized transverse emittance vs stage number and transverse
phase space before and after the acceleration to 2.5 TeV for the weak
and strong wakefield focusing properties.
0
−0.5
2
0
0
x/σx
0.5
200
4
150
6
100
8
time
2
200
4
stage no
100
8
50
10
150
6
time
50
10
stage no
Improved control of the emittance by feedback control to
minimize the final beam emittance (entropy).
Advanced Accelerator Concepts at UC Berkeley
Summary:
J.S. Wurtele, UC Berkeley
The development of a new generation of colliders beyond the LHC is central to the future of
high-energy physics. There is no new approved machine beyond the LHC and no consensus on
the optimal path to extend high-energy physics experiments into the multi-TeV energy range.
Indeed, the prospects for high-energy physics may be limited by our ability to build new
machines. Formidable challenges to achieving this goal exist, and numerous concepts are
being explored. Looking beyond the X-band collider design energies, our group has most
recently studied neutrino factories and muon colliders and plasma-based accelerators and
lenses. A brief overview of some of this work follows.
We investigated critical beam physics problems for neutrino factories and high-energy muon
colliders. There are significant challenges in the production, cooling, acceleration (and, for the
collider, collision) of the intense muon bunches. Our interest in the muon collider dates to
1995, when we investigated the suppression of collective instabilities in storage rings through
chromaticity variation. Over the last year we have studied muon beam cooling, perhaps the
most novel, and challenging, aspect of the neutrino factory and collider. We developed a
system of moments that capture the important physics of ionization cooling: energy loss,
stochastic scattering and angular momentum generation in material; acceleration by radio
frequency (RF) cavities; and focusing in solenoidal magnets. This formalism, analogous to the
Courant-Snyder description of quadrupole focusing, was used to categorize the solenoidal
lattice types of previous cooling channel geometries. We are currently investigating optical
stochastic cooling for muons. If it can be made to work, muons could be cooled well beyond
what can be achieved with ionization cooling.
We have spearheaded, in collaboration with researchers at LBNL and BNL, experimental
investigations of nonperturbative beam diagnostics based on spontaneous emission in wigglers.
The experiments, at the BNL Accelerator Test Facility, showed that careful measurements of
angular and spectral spontaneous emissions could be used to infer beam emittance. The
emittance was inferred by looking at the (average, not single-shot) spontaneous emission at
large angles where the energy spread and the emittance contributions to the spectrum can be
separated. Further work showed that longitudinal and transverse phase space information can
been obtained from statistical analysis of fluctuations in the radiation spectrum of a single
electron bunch. The underlying concept, originally put forth by Zolotorev and Stupakov, is that
uncorrelated shot noise fluctuations in longitudinal beam density result in incoherent radiation
with a spectrum that consists of spikes, with width inversely proportional to the bunch length.
More detailed modeling allowed for transverse phase space information to be inferred.
We have analyzed the hollow plasma channel as an accelerating structure. This analysis is
important in evaluating the performance of plasma-based structures. Beam quality, essential
for achieving a tight focus, can be degraded by instabilities associated with beam coupling to
transverse modes of accelerating structures. This generic phenomenon is present in plasma
structures as well as conventional structures. We analytically calculated beam coupling to the
fundamental and all higher-order azimuthal modes of the excited electromagnetic wave. Small
initial transverse displacements of the beam are shown to couple to deflecting modes in the
channel. The asymptotic growth rate of the resultant beam breakup instability was analyzed
and a method for reducing the growth was proposed.
We have been studying two areas of plasma lens dynamics. For the so-called overdense thick
lense, where the beam self-pinches in its own magnetic field, we have developed theoretical
and numerical techniques for predicting the evolution of the low order moments of the phase
space distribution of the beam. Our technique is an alternative to and extension of the
envelope equation model for systems with nonlinear force. It allows us to capture much of the
essential features of systems exhibiting a significant phase mixing and is in good agreement
with results of a particle-in-cell (PIC) simulation for the evolution of rms beam properties
including the relaxation of betatron oscillations and the emittance growth. We have modeled a
plasma lens experiment at LBNL (Leemans and co-workers) where observations of relativistic
beam focusing by a passive plasma lens have demonstrated a reduction in focusing strength
due to plasma return current. Reduced focusing was seen where a significant fraction of the
inductively driven return current in the plasma flows within the beam. The observations are in
good agreement with our envelope equation model and with particle-in-cell simulations.
Other research topics include numerical and theoretical studies of the production of ultrashort
electron bunches with optical injection schemes, fluid modeling of laser-plasma interactions
with steep transverse density gradients, and non-paraxial propagation of ultrashort, high-power
laser pulses in plasma channels.
The UC Berkeley program in advanced accelerator concepts has close connections with the
Center for Beam Physics at Lawrence Berkeley National Laboratory (LBNL). The proximity to
LBNL provides an ideal format for the training of graduate students and postdocs. This
connection gives the theory graduate students the opportunity to interact with a top beam
physics theory group and to participate in experimental programs, such as the laser-plasma
group of Leemans at LBNL. The PI has a leadership role in the Neutrino Factory and Muon
Collider Collaboration, and members of the group have worked closely with Muon Collaboration
scientists at the Center for Beam Physics and other DOE laboratories. The research on intense
muon sources offers the students and postdoctoral researchers the opportunity to work with
leading accelerator scientists throughout the world. Postdoctoral researchers have developed
collaborations with established accelerator physicists at the Center for Beam Physics and the
Advanced Light Source. Undergraduate research is also an important component of the
program. The activities of undergraduates include numerical investigation of the beam quality
expected in all-optical laser-plasma accelerators and pulse dynamics in free-electron lasers.
This work led to senior thesis, pre publications and publications in our faculty-refereed student
journal, Berkeley Scientific. Recent invited talks by group members have been given at Linac
2000, the 19th International Symposium On Lepton And Photon Interactions at High-Energies,
the ICFA Seminar On Future Perspectives In High-Energy Physics, and numerous APS meetings.
The PI was co-chair (with Stan Wojcicki) of the 2’nd International Workshop on Muon Storage
Rings for Neutrino Factories.
Current Staff:
•
•
•
•
•
•
•
•
Jonathan Wurtele
Alain Birzard
Ekaterina Backahus
Andrew Charman
Cameron Geddese
Emi Kawamura
Gregg Penn
Eun San Kim
Scientist
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Post-doc
Post-doc
Jonathan Wurtele (PI)
University of California, Berkeley
423 Birge Hall
Berkeley, California 94720-7300
PHONE: 510-643-1575
FAX: 510-486-6485
ADVANCED ACCELERATOR PHYSICS RESEARCH AT
NaI Calorimeter
David B. Cline, Principle Investigator
This group is mainly concerned with advances in accelerator physics for novel colliders
and high gradient accelerators. We describe three projects here:
1. Plasma Lens Focusing of e-/e+ beams at SLAC (E150)
The UCLA group has been working
with a SLAC group (Pisin Chen) for
sometime to develop the experiment
using the FFT Beam at SLAC. The first
ever plasma focussing of e+ beams was
observed recently. (The size of the
positron beam as result of the plasma
lens is shown.)
2. STELLA Experiment at the ATF at BNL. [The UCLA team's effort on the Coherent
Transition Radiation Monitor was very successful.]
The STELLA team has recently
observed the first example of the staging
of two laser accelerator systems. Such
staging is essential, if practical laser
driver accelerators for medicine,
industry and high energy applications is
to be accomplished. (The CTR detector
of the UCLA group is shown.)
3. Neutrino Factory and µ+µ− Collider Development. Measurement at TRIUMF of µ+ Multiple
Scattering (beam heating) Experiment.
The development of a Muon Storage
Ring Neutrino Factory or µ+µ- Collider
(Higgs Factory) requires beam phase
space compression or cooling. A source
of beam heating comes from the
multiple scattering of the beam in the
absorbers used for the cooling. The
UCLA group has joined with a group of
scientists from RAL, CERN and
TRIUMF to measure this scattering with
muons in the appropriate energy range.
First results from the experiment were
successful this spring. (A schematic of
the detector at TRIUMF is shown.)
Veto and timing
scintillators
WMPCs
Trigger
Scintillator
Vacuum tube and
collimation system
NaI Calorimeter
“Experimental, Theoretical and Computational Studies of Plasma Based
Concepts for Future High Energy Accelerators”
C. Joshi, W. Mori and C. Clayton - UCLA
Summary:
The UCLA Plasma Accelerator Group has had a strong program in the Advanced
Accelerator R & D area since 1984, supported by the Advanced Technology R & D
branch of the DOE’s Office of Science. This group has done pioneering work on many
concepts including the Plasma Beat Wave Accelerator, the Self-Modulated Laser Wake
Field Accelerator, the Plasma Lens, the Plasma Wake Field Accelerator and PlasmaFrequency Upshifters. Furthermore, the group has developed critical diagnostics
techniques to time, space, frequency and wave number resolve relativistic plasma
accelerating structures. An in-house theory and computational program have supported
the experiments. In addition, to first rate research results, this group has consistently
produced top-notch graduate students and mentored high-caliber research staff who
have gone on to become highly visible in the Beam Physics community.
In 1985, the UCLA group first showed that relativistic plasma waves could be excited
using the collinear optical mixing or the beat-wave technique. The electric field of such
waves was shown to be in excess of 1 GeV/m. This was followed up in 1993 by a
conclusive demonstration of acceleration of externally injected electrons by such waves.
The wave amplitude became large enough to actually trap the electrons in the wave
potential. Electrons were accelerated from 2 MeV to 30 MeV in about 1 cm which
implied an average gradient of ~ 2.8 GeV/m. The UCLA group has now embarked on
second-generation Plasma Beat Wave Acceleration experiments. The goal of these is to
demonstrate acceleration to ~ 100 MeV of a reasonable number of externally injected
electrons (say 109 per pulse) while maintaining a reasonable emittance (10 π mm mrad)
and an energy spread (∆γ/γ) ~ 0.1). To achieve this goal, Prof. Joshi’s group has built a
new facility called Neptune in collaboration with Professors Pellegrini and Rosenzweig of
the Physics Department. The Neptune facility houses a 1 TW, multi-line CO2 laser for
forming the plasma and exciting the plasma wave; a nominally 15 MeV photo-injector
linac to provide a suitable low emittance, high current beam for injection and associated
beam, laser and plasma diagnostics. The Neptune facility was completed in FY 2000
and experiments have begun as described above.
In addition to the Neptune project the UCLA group is currently engaged in the
SLAC E-157 experiment on the Plasma Wake Field Accelerator. The goal here is to
determine the issues associated with scaling the PWFA scheme to longer acceleration
lengths (> 1 m) and higher gradients (100s MeV/m). The experiment is a collaborative
effort between SLAC, UCLA, and USC groups. In its first year of operation, E-157 has
already yielded many significant new results on the transverse and longitudinal
dynamics of the 30 GeV FFTB drive beam as it passes through a dense plasma and on
the radiation given off by the transverse, periodic motion of this beam. It is the intent
of the collaboration to continue this work during the present year.
Journal Publications:
1. A. Lal, D. Gordon, K. Marsh, K. Wharton, C. Clayton and C. Joshi, “Exact forward
scattering of a CO2 laser beam from a relativistic plasma wave by time resolved
frequency mixing in AgGaS2,” Rev. Sci. Instrum. 68 (1), 690-693, January (1997).
2. D. Gordon, A. Lal, K. Wharton, C. E. Clayton, and C. Joshi, “2D Cherenkov Emission
Array for Studies of Relativistic Electron Dynamics in a Laser Plasma ,” Rev. Sci.
Instrum. 68 (1), 358-360, January (1997).
3. A. K. Lal, D. Gordon, K. Wharton, C. E. Clayton, K. A. Marsh, W. B. Mori, C. Joshi, M.
J. Everett, and T. W. Johnston, “Spatio-temporal dynamics of the resonantly excited
relativistic plasma wave driven by a CO2 laser,” Physics of Plasmas 4 (5), 1434,
May 1997.
4. A. K. Lal, K. A. Marsh, C. E. Clayton, C. Joshi, C. J. McKinstrie, J. S. Li, and T. W.
Johnston, “Transient Filamentation of a Laser Beam in a Thermal Force Dominated
Plasma,” Phys. Rev. Lett. 78, 670 (1997).
5. V. Malka, A. Modena, Z. Najmudin, A. E. Dangor, C. E. Clayton, K. A. Marsh, C.
Joshi, C. Danson, D. Neely and F. N. Walsh, “Second harmonic generation and its
interaction with relativistic plasma waves driven by forward raman instability in
underdense Plasmas,” Physics of Plasmas, 4 (4), 1127-1131 (1997).
6. W. B. Mori, “The Physics of the Nonlinear Optics of Plasmas at Relativistic
Intensities,” IEEE Journal of Quantum Electronics 33 (11), 1942-53, (1997).
7. J. Yoshii, C. H. Lai, T. Katsouleas, C. Joshi, and W. B. Mori, “Radiation from
Cherenkov Wakes in Magnetized Plasmas,” Physical Review Letters 79 (21),
4194-7 (1997).
8. K-C. Tzeng, W. B. Mori, and T. Katsouleas, “Electron Beam Characteristics from
Laser-Driven Wave Breaking,” Physical Review Letters 79 (26), 5258-5261
(December, 1997).
9. P. Muggli, R. Liou, J. Hoffman, and T. Katsouleas, and C. Joshi, “Generation of UltraShort, Discrete Spectrum Microwave Pulses Using the DC to AC Radiation
Converter,” Applied Physics Letters 72 (1), 19-21 (January, 1998).
10. D. Gordon, C. E. Clayton, T. Katsouleas, W. B. Mori, and C. Joshi, “Microbunching of
Relativistic Electrons using a Two-frequency Laser,” Physical Review E 57 (1), pp.
1035-1041 (1998).
11. C. E. Clayton, C. Joshi, K. A. Marsh, C. Pellegrini and J. Rosenzweig, “2nd
Generation Beatwave Experiments at UCLA,” Nuclear Instruments & Methods in
Physics Research A 410, 378-387 (1998).
12. D. Gordon, K.C. Tzeng, C.E. Clayton, A.E. Dangor, V. Malka, K.A. Marsh, A. Modena,
W.B. Mori, P. Muggli, Z. Najmudin, D. Neely, C. Danson, and C. Joshi, “Observation
of Electron Energies Beyond the Linear Dephasing Limit from a Laser-Excited
Relativistic Plasma Wave,” Physical Review Letters 80, (10), pp. 21332136(1998).
13. P. Muggli, R. Liou, C. H. Lai, J. Hoffman, C. Joshi and T. C. Katsouleas, “Generation
of Microwave Pulses from the Static Electric Field of a Capacitor Array by an
Underdense, Relativistic Ionization Front.” Physics of Plasmas 5, 2112, (May,
1998).
14. C. E. Clayton, K. C. Tzeng, D. Gordon, P. Muggli, W. B. Mori, C. Joshi, V. Malka, Z.
Najmudin, A. Modena, and A. E. Dangor, “Plasma Wave Generation in a SelfFocused Channel of a Relativistically Intense Laser Pulse,” Physical Review
Letters 81, 100-103 (July, 1998).
15. K-C. Tzeng and W. B. Mori, “Suppression of Electron Ponderomotive Blowout and
Relativistic Self-Focusing by the Occurrence of Raman Scattering and Plasma
Heating,” Physical Review Letters 81, 104-103 (July, 1998).
16. K. Wharton, S. Hatchett, S. Wilks, M. Key, J. Moody, V. Yanvosky, A. A. Offenberger,
B. Hammel and M. Perry, “Experimental Measurements of Hot Electrons Generated
by Ultra-Intense (> 1019 W/cm2) Laser-Plasma Interactions on Solid Density
Targets,” Physical Review Letters 81, 822-825 (1998).
17. R. G. Hemker, K. C. Tzeng, W. B. Mori, C. E. Clayton, and T. Katsouleas, “Computer
Simulations of Cathodless High-Brightness Electron Beam Production by Multiple
Laser Beams in Plasmas, Physical Review E 57, 5920-5928 (1998).
18. K. B. Wharton, C. Joshi, R. K. Kirkwood, S. H. Glenzer, K. G. Estabrook, B. B.
Afeyan, B. I. Cohen and J. D. Moody, “Obervation of Energy Transfer Between
Identical-Frequency Laser Beams in Flowing Plasmas,” Physical Review Letters
81, 2248-2251 (1998).
19. R. Assmann, P. Chen, F. J. Decker, R. Iverson, P. Raimondi, T. Raubenheimer, S.
Rokni, R. Siemann, D. Walz, D. Whittum, S. Chattopadhyay, W. Leemans, T.
Katsouleas, S. Lee, C. Clayton, C. Joshi, K. Marsh, W. Mori, and G. Wang, “Proposal
for a One GeV Plasma Wakefield Acceleration Experiment at SLAC,” Nuclear
Instruments and Methods in Physics Research A 410, 396-406 (1998).
20. J. Rosenzweig, S. Anderson, K. Bishofberger, X. Ding, A. Murokh, C. Pellegrini, H.
Suk, A. Tremaine, C. Clayton, C. Joshi, K. Marsh, P. Muggli, “The Neptune
photoinjector,” Nuclear Instruments and Methods in Physics Research A 410,
437-451 (1998).
21. K. B. Wharton, C. Joshi, R. K. Kirkwood, S. H. Glenzer, K. G. Estabrook, B. B.
Afeyan, B. I. Cohen and J. D. Moody, “ Energy Transfer Between IdenticalFrequency Laser Beams in Flowing Plasmas,” Physics of Plasmas, Vol. 6, No. 5,
pp. 2144-2149, May (1999).
22. D. Bernard, F. Amiranoff, E. Esarey, W. Leemans, and C. Joshi, “”Alternative
intrepretation of Nucl. Instr. And Meth. In Phys. Res. A 410 (1998 357 (H. Dewa et
al.)),” Nucl. Instr. And Meth. In Phys. Res. A, Vol. 432, pp. 227-231 (1999).
23. P. Muggli, K. A. Marsh, S. Wang, C. E. Clayton, S. Lee, T. C. Katsouleas, and C.
Joshi, “Photo-Ionized Lithium Source for Plasma Accelerator Applications,” IEEE
Trans. On Plasma Science, Vol. 27, No. 3, 791-799, (June 1999).
24. B. J. Duda, R. G. Hemker, K.C. Tzeng, and W. B. Mori, “A Long Wavelength Hosing
Instability in Laser-Plasma Interactions,” Physical Review Letters 83, (1), 1978
(1999).
25. R.K. Kirkwood, D. S. Montgomery, B. B. Afeyan, J. D. Moody, B. J. MacGowan, C.
Joshi, K. B. Wharton, S. H. Glenzer, E. A. Williams, P. E. Young, W. L. Kruer, K. G.
Estabrook, and R. L. Berger, “Observation of the Nonlinear Saturation of Langmuir
Waves Driven by Ponderomotive Force in a Large Scale Plasma,” Physical Review
Letters, Vol. 83, 2965-2968, October (1999).
26. S. Ya. Tochitsky, R. Narang, C. Filip, C. E. Clayton, K. Marsh, and C. Joshi,
“Generation of 160-ps terawatt-power CO2 laser pulses,” Optics Letters, Vol. 24,
No. 23, pp. 1717-1719, December (1999).
27. T. Katsouleas, C. Joshi, W. B. Mori, “Plasma Physics with GeV Electron Beams,”
Comments on Plasma Physics and Controlled Fusion, Comments on
Modern Physics, Vol 1, No. 3, Part C. pp. 99-109 (1999).
28. Z. Najmudin, A. E. Dangor, A. Modena, C. Clayton, D. Gordon, C. Joshi, K. Marsh, P.
Muggli, V. Malka, C. Danson, D. Neely, and F. N. Walsh, “Investigation of a
channeling high intensity laser-beam in underdense plasmas,” submitted to IEEE
Tran. On Plasma Sci., 2000.
29. Z. Najumdin, R. Allott, F. Amiranoff, E. Clark, C. Danson, D. Gordon, C. Joshi, K.
Krushelnick, V. Malka, D. Neely, M. Salvati, M.I.K. Santala, M. Tatarakis, A. E.
Dangor, “Measurement of forward Raman scattering and electron acceleration from
high intensity laser plasma interactions at 527 nm, “ submitted to IEEE Tran. On
Plasma Sci., 2000.
30. H. Suk, C. E. Clayton, C. Joshi, T C.. Katsouleas, P. Muggli, R. Narang, C. Pellegrini,
J. B. Rosenzweig, “Plasma Source Test and Simulation Results for the Underdense
Plasma Lens Experiment at the UCLA Neptune Laboratory,” submitted to IEEE
Tran. On Plasma Sci., 2000.
31. D. F. Gordon, W. B. Mori, and C. Joshi, “On the possibility of electromagnetically
induced transparency in a plasma: Part I: Infinite Plasma,” Physics of Plasmas,
Vol. 7, No. 8, 3145-3155(2000).
32. D. F. Gordon, W. B. Mori, and C. Joshi, “On the possibility of electromagnetically
induced transparency in a plasma: Part II: Bounded Plasma,” Physics of Plasmas,
Vol. 7, No. 8, 3156-3166 (2000).
33. M. J. Hogan, C. E. Clayton, P. Muggli, R. Siemann, and C. Joshi, “E-157: A 1.4
Meter-long Plasma Wakefield Acceleration Experiment Using the 30 GeV Electron
Beam from the SLAC Linac,” Physics of Plasmas, Vol 7, No. 5 (2000).
34. Y. Sakawa and C. Joshi, “Growth and nonlinear evolution of the modified Simon-Hoh
instability in an electron beam-produced plasma, Physics of Plasmas, Vol. 7, No.
5, 1774-1780 (2000).
35. B. J. Duda and W. B. Mori, “A Variational Principle Approach to Short-Pulse Laser
Plasma Interactions in Three Dimensions,” Physical Review E, (Feb., 2000).
36. D. F. Gordon, W. B. Mori, and T. M. Antonsen, Jr., “A Ponderomotive Guiding Center
Particle-in-Cell Code for Efficient Modeling of Laser-Plasma Interactions,” submitted
to IEEE Trans. On Plasma. Sci.(2000).
37. L.O. Silva, W. B. Mori, R. Bingham, J. M. Dawson, T. M. Antonsen and P. Mora,
“Photon Kinetic PIC Code for Laser-Plasma Interactions,” submitted to IEEE Trans.
On Plasma. Sci.(2000).
38. S. Lee, T. Katsouleas, R. G. Hemker, and W. B. Mori, “Simulations of a meter long
plasma wakefield accelerator, to appear in Phys. Rev. E, (2000).
39. R. G. Hemker, W. B. Mori, S. Lee, and T. Katsouleas, “Dynamic Effects in Plasma
Wakefield Excitation,” submitted to Phys. Rev. Spec. Top. Acc. & Beams, (2000).
40. C. Ren, E.S. Dodd, D. Gordon, and W. B. Mori, “Subharmonic Resonances of Driven
Relativistic Plasma Waves: Exponential and Explosive Growth,” submitted to Phys
Rev. Lett. (2000).
41. R. G. Hemker, N. Spence, W. B. Mori, and T. Katsouleas, “Three-dimensional PIC
simulations of radiation for cerenkov wakes,” in preparation for Physics of
Plasmas.
42. R. G. Hemker, E.S. Dodd, R. Fonseca, and W. B. Mori, “Three-dimensional PIC
simulations of all optical injection,” in preparation for Phys. Rev. ST-AB.
43. S. Lee, R. G. Hemker, T. Katsouleas, and W. B. Mori, “Wakefields from positron
drivers,” in preparation.
44. R. G. Hemker, E. S. Dodd, W. B. Mori, S. Lee and T. Katsouleas, “Three-dimensional
wake structures from asymmetric drive beams,” in preparation.
Conference Publications:
45. C. Joshi, “Laser Accelerators: Experiments, Computations and Prospects,”
proceedings of the PAC Conference, Vancouver, Canada, May 12-16, 1997.
46. D. Gordon, C. E. Clayton, W. B. Mori, C. Joshi, T. Katsouleas, “Optical Bunching of
Relativistic Electrons for Injection into a GeV Plasma Beatwave,” proceedings of the
PAC Conference, Vancouver, Canada, May 12-16, 1997.
47. C. E. Clayton, C. Joshi, K. A. Marsh, C. Pellegrini, and J. Rosenzwieg, “The NEPTUNE
Facility for 2nd Generation Advanced Accelerator Experiments,” proceedings of the
PAC Conference, Vancouver, Canada, May 12-16, 1997.
48. T. Katsouleas, S. Chattopadhay, W. Leemans, R. W. Assmann, P. Chen, F.J. Decker,
S. Heifets, R. Iversen, T. Kotseroglou, S. Rokni, R. H. Siemann, D. Waltz, D.
Whittum, C. Clayton, C. Joshi, K. Marsh, and W. Mori, “A Proposal for a 1 GeV
Plasma Wakefield Acceleration Experiment at SLAC,” proceedings of the PAC
Conference, Vancouver, Canada, May 12-16, 1997.
49. C. E. Clayton, P. Muggli, D. Gordon, K-C. Tzeng, W. B. Mori, C. Joshi, A. Modena, Z.
Najmudin, A. E. Dangor, V. Malka, and D. Neely, “The Observation of SelfChanneling of a Relativistically-Intense Laser Pulse in an Underdense Plasma,” LEOS
‘97 Proceedings, San Francisco, CA, November 10-13, 1997.
50. P. Muggli, K. A. Marsh, S. Wang, C. E. Clayton, T. C. Katsouleas, and C. Joshi,
“Meter Long, Homogeneous Plasma Source for Advanced Accelerator Applications,”
8th Workshop on Advanced Accelerator Concepts Proceedings, Baltimore, MD, July 511, 1998.
51. H. Suk, C. E. Clayton, R. Narang, P. Muggli, J. Rosenzweig, C. Pellegrini, and C.
Joshi, “Test Results of the Plasma Source for Underdense Plasma Lens Experiments
at the UCLA Neptune Lab,” 8th Workshop on Advanced Accelerator Concepts
Proceedings, Baltimore, MD, July 5-11, 1998.
52. J. R. Hoffman, P. Muggli, T. C. Katsouleas, and C. Joshi, “Photon Acceleration-Based
Radiation Sources,” 8th Workshop on Advanced Accelerator Concepts Proceedings,
Baltimore, MD, July 5-11, 1998.
53. P. Muggli, K. A. Marsh, S. Wang, C. E. Clayton, S. Lee, T. C. Katsouleas, and C.
Joshi, “Meter Long Homogeneous Plasma Sources for Advanced Accelerator
Applications,” LASERS’98 proceedings, Tucson, Arizona, December 7-11, 1998.
54. P. Muggli, J. Yoshii, T. C. Katsouleas, C. E. Clayton, and C. Joshi, “Cerenkov
Radiation from a Magnetized Plasma, a Diagnostic for PBWA Experiments,”
proceedings of the PAC Conference, New York City, NY, March 28- April 2, 1999.
55. P. Muggli, J. R. Hoffman, K. A. Marsh, S. Wang, C. E. Clayton, T. C. Katsouleas, and
C. Joshi, “Lithium Plasma Sources for Acceleration and Focusing of Ultra-Relativistic
Electron Beams,” proceedings of the PAC Conference, New York City, NY, March 28April 2, 1999.
56. H. Suk, C. E. Clayton, G. Hairapetian, C. Joshi, M. Loh, P. Muggli, R. Narang, C.
Pellegrini, and J. B. Rosenzweig, “Underdense Plasma Lens Experiment at the UCLA
Neptune Laboratory,” proceedings of the PAC Conference, New York City, NY,
March 28- April 2, 1999.
57. D. Gordon, W. B. Mori, and C. Joshi, “Electromagnetically Induced Transparency
(EIT) in a Bounded Plasma and its Relation to Beat Wave Physics,” proceedings of
the PAC Conference, New York City, NY, March 28- April 2, 1999.
58. S. Anderson, J. Rosenzweig, K. Bishofberger, X. Ding, T. Holden, A. Murokh, C.
Pellegrini, H. Suk, A. Tremaine, C. Clayton, K. Marsh, and P. Muggli, “
Commissioning of the Neptune Photoinjector,” proceedings of the PAC Conference,
New York City, NY, March 28- April 2, 1999.
59. R. Assmann, P. Catravas, S. Chattopadhyay, W. P. Leemans, P. Volfbeyn, P. Chen,
F-J. Decker, R. Iverson, P. Raimondi, M. Hogan, T. Raubenheimer, S. Rokni, R. H.
Siemann, D. Walz, D. Whittum, C. Clayton, C. Joshi, K. Marsh, W. Mori, G. Wong, T.
Katsouleas, S. Lee, and P. Muggli, “Experimental Progress Towards E-157: A GeV
Plasma Accelerator,” proceedings of the PAC Conference, New York City, NY, March
28- April 2, 1999.
60. S. DiMaggio, S. Archambault, P. Catravas, P. Volfbeyn, W. P. Leemans, K. Marsh, P.
Muggli, S. Wang, and C. Joshi, “Development of One Meter-Long Lithium Plasma
Source and Excimer Mode Reduction for Plasma Wakefield Applications,”
61. B. J. Duda and W. B. Mori, “A Variational Principle Approach to the Evolution of
Short-Pulse Laser Plasma Drivers,” proceedings of the PAC Conference, New York
City, NY, March 28- April 2, 1999.
62. R. G. Hemker, F. S. Tsung, V. K. Decyk, W. B. Mori, S. Lee, and T. Katsouleas,
“Development of a Parallel Code for Modeling Plasma Based Accelerators,”
63. S. Y. Tochitsky, C. E. Clayton, K. A. Marsh, R. Narang, C. Filip, and C. Joshi, “ A twowavelength terawatt CO2 laser system for the plasma beat wave accelerator,”
Proceedings of the Conference on Laser and Electro-optics (CLEO ’99), Baltimore,
MD, May 23-28, 1999.
64. S. Y. Tochitsky, R. Narang, C. Filip, B. Blue, C. E. Clayton, K. A. Marsh, and C. Joshi,
“Amplification of Two-Wavelength CO2 Laser Pulses to Terawatt Level,” Proceedings
of the LASERS ’99 Conference, Quebec City, Canada, December 1999.
Current Staff:
• Professor Chan Joshi
• Dr. Chris Clayton
Co-P.I.
• Prof. Warren Mori
Co-P.I.
• Ken Marsh, Principle
Development Engineer
• Dr. Sergei Tochitsky
Postdoc
Current Students:
•
•
•
•
•
•
•
Shuoqin Wang
Catalin Filip
Ritesh Narang
Brent Blue
Kari Sanders
Brian Duda
Chun-kun Huang
Chan Joshi (PI)
University of California – Los Angeles
Boelter Hall 7731-L
405 Hilgard Avenue
Los Angeles, California 90024-1594
PHONE: 310/825-7279
FAX: 310/206-8220
Theoretical and Experimental Studies in Accelerator Physics
Profs. James Rosenzweig and Claudio Pellegrini,
UCLA Dept. of Physics and Astronomy
Summary:
The activities on this grant encompass the research interests of Profs. James
Rosenzweig and Claudio Pellegrini. Prof. Rosenzweig has led the development of
the Neptune photoinjector, its associated basic beam physics and diagnosis
work, and its (non-beatwave) plasma acceleration program. Prof. Pellegrini has
led the effort to develop a high gradient inverse free-electron laser experiment
for Neptune. In addition to this on-campus program, which is a part of the larger
Neptune collaboration with Prof. C. Joshi of UCLA Electrical Engineering, both
PI's have off-campus experimental programs partially or fully supported my this
grant at BNL, FNAL, LLNL and SLAC.
Some of the highlights of the last year's research include:
1. The commissioning of the Neptune photoinjector has been completed. The
electron pulses in this state-of-the art system have been compressed using a
magnetic chicane to sub-picosecond length. This pulse length measurement
has been accomplished using coherent transition radiation (CTR)
interferometry. Emittance growth due to non-inertial space charge and
coherent synchrotron radiation is now being measured using the UCLAdeveloped single shot, slit-based phase space reconstruction method to give
insight into these until recently unexplored basic beam physics effects.
2. A new initiative has been started to make single-shot CTR-based pulse length
measurements with a multi-channel polychromator. This effort is being
undertaken in collaboration with the U.Tokyo-U.Tohoku group, and will lead to
a critical diagnostic for the plasma beatwave acceleration (PBWA).
3. Development of new chicane systems for Neptune, the ATF at BNL, and LLNL,
has produced a number of new concepts for longitudinal manipulations of subpicosecond beam pulses. Analytical and computational studies have been
completed on a scheme to recover phase locking between a beatwave-sliced
injected beam and the laser beatwave. The single-shot CTR polychromator is
to be used to diagnose the effectiveness of this scheme. In addition, a new
dogleg beamline has been modeled, is being constructed for Neptune, which
will allow generation of a beam with a long ramp and sharp fall. This beam is
to be used for a high-transformer ratio plasma wakefield accelerator (PWFA)
experiment.
4. Photocathode development has proceeded on many fronts. A single crystal
copper photocathode was used for the first time at Neptune to great success.
A high current multi-keV electron beam to clean cathodes in situ is nearing the
commissioning stage. Design work performed in collaboration with P. Michelato
(INFN-Milano) which will enable a load-lock cathode system (for, e.g. cesium
telluride) to be used at on the high gradient rf gun at Neptune has made
significant progress.
5. A plasma source at Neptune has been reconditioned for use in an underdense
plasma lens experiment on the dogleg beamline.
6. A new high density (<1E15/cc) plasma source was developed in collaboration
with FNAL, for use at the A0 photoinjector/compressor. Compressed 17 MeV, 1
psec, 5 nC beam pulses were essentially brought to a stop by the PWFA effect
in this 9 cm long underdense plasma source, with the momentum spectrum of
this “end-point” beam well characterized. Acceleration of the tail of such a
beam was observed to be in excess of 100 MeV/m. This work is currently being
written up for publication in Physical Review Letters (PRL).
7. A new method of creating phase-locked, fsec beam pulses in plasma waves by
trapping background plasma electrons was proposed and analyzed by our
group. This scheme, which is much simpler that those using colliding laser
pulses previously proposed, uses only a drive beam PWFA that traverses a
sharp density gradient in the plasma. Phase mixing near the transition
produces local wave-breaking, and a trapped electron population. By
appropriate tailoring of the density profile in simulations, it has been found
that a very high quality (low emittance, small energy spread) electron beam
can be “injected” into the plasma wave. This proposal has been published in
PRL and is now under study for a possible Neptune experiment.
8. An inverse free-electron laser experiment that utilizes the TW 10 micron Mars
laser and the photoinjector at Neptune. This ultra-high power laser beam is
handled well by small f/# focusing, which produces a large Guoy phase shift
during the IFEL interaction. A detailed dynamics study has led to an IFEL
experimental design using a tapered undulator, which has a small longitudinal
gap near the focus in order to mitigate these strong phase shift effects.
Undulator construction studies are now underway in collaboration with the
Kurchatov Institute in Moscow, with whom UCLA has previously built
sophisticated undulator systems.
9. Detailed experimental studies of transverse beam profile monitors have been
conducted at the BNL ATF. Fundamental saturation and collective (intense
space-charge field) effects were shown to limit the use of the popular Ce:YAG
crystal to beam intensities smaller than encountered in many advanced
accelerator and FEL experiments. Theoretical and experimental studies of
optical transition radiation from non-ideal surfaces were also performed.
10. Two new models of the high gradient S-band 1.6 cell rf gun were created at
UCLA in the last year. One was developed jointly with G. Le Sage of LLNL, and
used for an experimental exploration of space-charge effects in emittance
measurements. By comparison of slit-based measurements with the results of
quad scans and modeling with the codes HOMDYN and PARMELA, it was
determined that at moderate energies, near 5 MeV, plasma (space-charge
dominated beam) effects dominate the results of the quad scan. An analytical
theory of this effect is now under study.
Publications:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
H. Suk, N. Barov, J. B. Rosenzweig and E. Esarey, “Plasma Electron Trapping and
Acceleration in a Plasma Wake Field Using a Density Transition,” Phys. Rev. Lett.,
86, 6 (2001).
S.G. Anderson and J. B. Rosenzweig, “Nonequilibrium transverse motion and
emittance growth in ultrarelativistic space-charge dominated beams,” Physical
Review Special Topics Accelerators and Beams 3, 094201 (2000).
J. B. Rosenzweig, Fundamentals of Beam Physics, (textbook, World Scientific,
2001).
N. Barov, J. B. Rosenzweig, M. E. Conde, W. Gai, and J. G. Power, “Observation of
plasma wakefield acceleration in the underdense regime," Physical Review Special
Topics Accelerators and Beams 3 011301 (2000).
N. Barov, J. B. Rosenzweig, M. E. Conde, W. Gai, and J. G. Power, “Observation of
plasma wakefield acceleration in the underdense regime,” Physical Review Special
Topics Accelerators and Beams 3 011301 (2000).
J.B. Rosenzweig, A. Murokh and A. Tremaine, "Coherent Transition Radiation-Based
Measurement of Longitudinal Beam Shapes," Advanced Accelerator Concepts Eighth
Workshop Proceedings, 38 472, (AIP, 1999).
H. Suk, et al., “Test results of the plasma source for underdense plasma lens
experiments at the UCLA Neptune Lab,” Advanced Accelerator Concepts Eighth
Workshop Proceedings, 501 472, (AIP, 1999).
J. B. Rosenzweig, Greg LeSage, "Synchronization of Sub-picosecond Electron and
Laser Pulses," Advanced Accelerator Concepts Eighth Workshop Proceedings, 501
472, (AIP, 1999).
J. Rosenzweig " Highlights of AAC 2000 Workshop," to appear in the Proceedings of
the 2000 Linac Conference (Monterey).
N. Barov, et al., "Ultra-high gradient deceleration of compressed electron beams in
plasma," submitted to Phys. Rev. Lett.
S. Anderson, et al., “Initial measurements on the Neptune photoinjector,” to appear
in the Proceedings of the Advanced Accelerator Concepts Ninth Workshop.
M. C. Thompson and J. B. Rosenzweig, "Production and synchronization of electron
beams from RF photoinjector/compressor systems for ultra-fast applications," to
appear in the Proceedings of the Advanced Accelerator Concepts Ninth Workshop.
P. Musumeci and C. Pellegrini, "An ultra-high gradient inverse free-electron laser
accelerator at the Neptune laboratory," to appear in the Proceedings of the
Advanced Accelerator Concepts Ninth Workshop.
H. Suk, N. Barov, J. B. Rosenzweig and E. Esarey, “Optimization of Density
Transition-induced Trapping in a Plasma Wake Field Accelerator,” submitted to
Physical Review Special Topics Accelerators and Beams.
C. Pellegrini, "Design Considerations for a SASE X-ray FEL," to be published in
Nuclear Instruments and Methods A (Proceedings of the 22nd International FEL
Conference)
Current Staff:
Staff wholly or partially supported by this grant:
•
•
•
•
•
•
•
•
•
•
•
•
•
Pellegrini, C.
Rosenzweig, J.
Suk, H.
Barov, N.
Boucher, S.
Anderson, S.
Agusstson, R.
England, J.
Murokh, A.
Musumeci, P.
Thompson, M.
Muller, C.
Perelli, M.
PI
PI
Research Scientist
Postdoctoral Researcher
Engineering Specialist
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Undergraduate Student
James B. Rosenzweig (PI-on campus) and Claudio Pellegrini (PI-off campus)
Department of Physics and Astronomy
University of California, Los Angeles
Los Angeles, California 90095
PHONE:
FAX:
E-MAIL:
Website:
310/206-4541
608/[email protected]
or [email protected]
http://pbpl.physics.ucla.edu
Figure 1(a). Deceleration to near stopping of PWFA drive beam in blow-out
regime experiments (UCLA/FNAL A0 collaboration), over 150 MeV/m, equivalent
stopping power of liquid lithium with 8 orders of magnitude less density
Figure 1(b). Acceleration of drive beam tail in UCLA/FNAL experiment, up to 70
MeV/m observed. New instrumentation is expected to double this gradient.
Interferometer Signal
Compressor Bend Angle = 22.5º
Normalized Signal
1.2
1.0
0.80
0.60
σ = 1.0 psec
t
0.40
Normalized Signal
Time Domain Fit
0.20
0.0
0
5
10
15
20
Position [psec]
Figure 2. Martin-Puplett interferogram of coherent transition radiation from psec
compressed at Neptune photoinjector, and picture of new compressor built at
UCLA for use at BNL ATF, allowing compression of 0.15 nC beam to 30 microns.
Figure 3. Simulation of density transition-induced PWFA injection scheme, showing small energy spread, sub-psec beam extracted from background plasma.
Theoretical Problems in Accelerator Physics
N. M. Kroll - UCSD
Summary:
This grant was initiated February 15, 1993, renewed twice, and currently scheduled to
continue through February 14, 2002. It has been primarily devoted to the design of
advanced accelerating structures and related RF components. For the last five years or
so I have (apart from minor secretarial assistance) been the sole individual supported
by the grant, and as a consequence all of my work on this grant has been in close
collaboration with other groups, in particular with the ARD-A, NLC, and ARD-B groups at
SLAC and with the Schultz group at UCSD.
The major activity has been collaboration with ARD-A and NLC on the conceptualization
and development of the NLC Damped Detuned accelerating Structure (DDS). The
underlying concept and initial analysis were first presented at LINAC94 (SLAC-PUB6616), and a review of progress and concept to date of presentation (PAC97) is given in
[6]. The more recent activity related to this work is reported in publications from 1997
on [nos. 3-12, 16-19,23-27,30,32-36]. Briefly, the structure is a multi-cell X-band
accelerating structure with a dipole mode detuning profile and damping manifolds,
waveguide like structures, which run along the length of the structure. The purpose of
these features is to suppress the transverse wakefield, accomplished initially by the
detuning and subsequently by the damping manifolds. The latter also serve importantly
as vacuum pumping manifolds and, by spectral analysis of their RF radiation, provide
beam position and structure misalignment monitoring. These latter aspects are
discussed in [4,6,9,18, and 27].
In collaboration with the ARD-A RF components group, we have participated in the
development of multimoded waveguide components for efficient high power handling
and distribution [13]. We emphasized the importance and initiated the study of planar
components [21,22] and also suggested the use of the TE12 mode for low loss
transmission in a multimoded Delay Line Distribution System (DLDS) [31].
We originated a new time domain simulation procedure for the design of waveguide
couplers for accelerator structures. It provides a direct determination of the complex
reflection coefficient for the traveling waves within the structure by the coupler. All of
the collaborative groups mentioned in the introduction have participated in its
implementation and application to a wide variety of structures [33]. To wit: a series of
structures designed for the study of the high power RF breakdown and damage
problem, and the zipper and PBG structures discussed below. It is also being used to
study the long standing excess coupler fields problem, and one solution [33] is
scheduled for implementation in the high power breakdown studies.
We proposed a planar accelerating structure for W band implementation suited for
electro-discharge machining (EDM) and diffusion bonding assembly. Analysis has been
carried out in collaboration with the ARD-B group at SLAC and the Schultz group at
UCSD. It was first reported at PAC99 [28] and dubbed the Zipper. A 25 cell version
has been fabricated and subjected to RF measurement by the ARD-B group. Results
were reported at AAC2000 [39]. The structure is described together with a figure in the
contribution of the Schultz group to this volume.
We have been collaborating with the Schultz group on Photonic Band Gap (PBG)
structures since they were first proposed for accelerator cavity application at AAC92.
The outer walls of the cells which constitute a periodic accelerator structure are
replaced by a periodic array of posts which are designed to trap the accelerating mode
while leaving higher order modes free to propagate out from the central region. For W
band application, the openness of the structure is very attractive from the point of view
of pumping. A five cell X band model with couplers has been designed and is being
fabricated by the ARD-B group. Further details and figures are contained in the Schultz
group contribution and in [1,2,20,and 33].
Finally, we have also been collaborating with the Schultz group on the analysis and
computer simulation of Left-Handed Metamaterials [37,38, and 40] that they have
invented. Again we refer to the Schultz group report for details.
Publications:
1.
2.
3.
4.
5.
6.
D.R. Smith, Derun Li, D.C. Vier, N. Kroll, S. Schultz, and H. Wang, “Recent
Progress on Photonic Band Gap Accelerator Cavities,” Advanced Accelerator
Concepts, Lake Tahoe, CA 1996, Ed S. Chattopadhyay, AIP Conf. Proc. 398, 518
(1997).
Derun Li, N. Kroll, D. R. Smith, and S. Schultz, “Wake-Field Studies on Photonic
Band Gap Accelerator Cavities,” Proceedings of the 7'th Workshop on Advanced
Accelerator Concepts, Lake Tahoe, CA 1996, Ed S. Chattopadhyay, AIP Conf.
Proc. 398, 528 (1997).
N. M. Kroll, R.M. Jones, et al, “Recent Results & Plans For The Future on SLAC
Damped Structures (DDS),” SLAC-PUB-7387, Advanced Accelerator Concepts,
Lake Tahoe, CA 1996, Ed S. Chattopadhyay, AIP Conf. Proc. 398, 455 (1997).
R.M. Jones, N. M. Kroll, et al, “Analysis And Application Of Manifold Radiation In
DDS: First Experiences,” SLAC-PUB-7388, Advanced Accelerator Concepts, Lake
Tahoe, CA 1996, Ed S. Chattopadhyay, AIP Conf. Proc. 398, 465 (1997).
R.M. Jones, R.H. Miller, and N. M. Kroll, “A Rapid Re-Design Method for the NLC
DDS and Phase Stability of the Accelerating Mode: Implementation and Results,”
NLC-Note #24, April 1977.
N.M. Kroll, “The SLAC Damped Detuned Structure. Concept and Design,” (invited
paper) SLAC-PUB-7541, Proceedings of the 1997 Particle Accelerator Conference,
Vancouver, B. C., May 1997, 429 (1998).
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
R. M. Jones, N. M. Kroll, R. H. Miller, R. Ruth, and J. Wang, “Advanced Damped
Detuned Structure (DDS) Development at SLAC,” SLAC-PUB-7537, Proceedings of
the 1997 Particle Accelerator Conference, Vancouver, B. C., May 1997, 548
(1998).
R. M. Jones, N. M. Kroll, and R. H. Miller, “Spectral Function Calculation of Angle
Wakes, Wake Moments, and Misalignment Wakes of the SLAC Damped Detuned
Structures (DDS),” SLAC-PUB-7538, Proceedings of the 1997 Particle Accelerator
Conference, Vancouver, B. C., May 1997, 551 (1998).
R. M. Jones, N. M. Kroll, et al, “Analysis and Application of Microwave Radiation
from The Damping Manifolds of the SLAC Damped Detuned Structures (DDS),”
SLAC-PUB-7539, Proceedings of the 1997 Particle Accelerator Conference,
Vancouver, B. C., May 1997, 554 (1998).
R. D. Ruth, ... , N. Kroll, et al, “Results from the SLAC NLC Test Accelerator,”
SLAC-PUB-7532, Proceedings of the 1997 Particle Accelerator Conference,
Vancouver, B. C., May 1997, 439 (1998).
C. Adolphsen, ... , N. Kroll, et al, “Measurement of Wake Field Suppression in a
Damped and Detuned X Band Accelerator Structure,” SLAC-PUB-7519, (1997),
Submitted to Phys. Rev Lett.
M. Dehler, I. Wilson, W. Wuensch, R.M. Jones, N. M. Kroll, R. H. Miller, “Design of
a 30 GHz Damped Detuned Structure,” Proceedings of the 1997 Particle
Accelerator Conference, Vancouver, B. C., May 1997, 518 (1998).
S. G. Tantawi, ... ,N. Kroll, et al, “A Multi-Moded RF Delay Line Distribution
System for the Next Linear Collider,” http://www.cern.ch/ accelconf/ (epac98 item
305), Proceedings of the 6th European Particle Accelerator Conference (EPAC98),
Stockholm, Sweden, June, 1998, 305 (1998).
K. Eppley, N. Kroll, et al, “A Four-Port Launcher for a Multi-Moded DLDS Power
Distribution System,” SLAC-PUB-7867, Proceedings of the 6th European Particle
Accelerator Conference (EPAC98), Stockholm, Sweden, June, 1998, 1779 (1998).
R. M. Jones, N. M, Kroll, and R. H. Miller, ‘Application of a Mapping Function
Technique to the Design of Damped Detuned Structures and Rapid Calculation of
Their Wakefields, ‘ SLAC-PUB-7933, Proceedings of the XIX International Linac
Conference (LINAC98), Chicago, Illinois, August, 1998, 288 (1998).
R. M. Jones, N. M. Kroll, et al, ‘The Dipole Wakefield for a Rounded Damped
Detuned Linear Accelerator with Optimized Cell-to-Manifold Coupling,” SLAC-PUB7934, Proceedings of the XIX International Linac Conference (LINAC98), Chicago,
Illinois, August, 1998, 282 (1998).
R. M. Jones, N. M. Kroll, et al, “Effects of Alternating Cell Misalignments on the
DDS,” SLAC-PUB-7935, Proceedings of the XIX International Linac Conference
(LINAC98), Chicago, Illinois, August, 1998, 285 (1998).
M. Seidel,...,N. M. Kroll, et al, “Absolute Beam Position Measurements in an
Accelerator Structure,” Nucl. Instrum. Meth. A404, 231 (1998).
J. Klingmann, ... ,N. Kroll, et al, “Fabrication of DDS-3, an 11.4 GHz DampedDetuned Structure,” Proceedings of the 1999 Particle Accelerator Conference
(PAC99), New York, New York, March, 1999, 777 (1999).
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
N. Kroll, S. Schultz, D. R. Smith, and D. V. Vier, “Photonic Band Gap Accelerator
Cavity Design at 90 GHz,” Proceedings of the 1999 Particle Accelerator
Conference (PAC99), New York, New York, March, 1999, 830 (1999).
C. D. Nantista, W. R. Fowkes, N. M. Kroll, and S. G. Tantawi, “Planar Waveguide
Hybrids for Very High Power RF,” SLAC-PUB-8142, Proceedings of the 1999
Particle Accelerator Conference (PAC99), New York, New York, March, 1999, 1432
(1999).
S. G. Tantawi, N. M. Kroll, and K. Fant, “RF Components Using Over-Moded
Rectangular Waveguides for the Next Linear Collider Multi-Moded Delay Line RF
Distribution System,” Proceedings of the 1999 Particle Accelerator Conference
(PAC99), New York, New York, March, 1999, 1435 (1999).
J. W. Wang, ... ,N. Kroll, et al, “Accelerator Structure R&D for Linear Colliders,”
Proceedings of the 1999 Particle Accelerator Conference (PAC99), New York, New
York, March, 1999, 3423 (1999).
R. M. Jones, N. M. Kroll, et al, “The Transverse Long-Range Wakefield in RDDS1
for the JLC/NLC X-Band Linacs,” SLAC-PUB-8103, Proceedings of the 1999 Particle
Accelerator Conference (PAC99), New York, New York, March, 1999, 3468 (1999).
R.M. Jones, N. M. Kroll, and R.H. Miller, “Including Internal Losses in the
Equivalent Circuit Model of the Slac Damped Detuned Structure (DDS),” SLACPUB-8102, Proceedings of the 1999 Particle Accelerator Conference (PAC99), New
York, New York, March, 1999, 3471 (1999).
R.M. Jones, ... , N. M. Kroll, et al, “Emittance Dilution and Beam Break Up in the
JLC/NLC,” SLAC-PUB-8101, Proceedings of the 1999 Particle Accelerator
Conference (PAC99), New York, New York, March, 1999, 3474 (1999).
C. Adolphsen, ..., N. Kroll, et al, “Wakefield and Beam Centering Measurements of
a Damped and Detuned X-Band Accelerator Structure,” SLAC-PUB-8174,
York, March, 1999, 3477 (1999).
N.M. Kroll, et al, “Planar Accelerator Structures for Millimeter Wavelengths,”
York, March, 1999, 3612 (1999).
C. Adolphsen, ..., N. Kroll, et al, “International Study Group Progress Report on
Linear Collider Development,” SLAC-R-559, April 2000.
R. M. Jones, N. M. Kroll, et al, “Advances in the SLAC RDDS: Modeling Manifold
Damping and its Effect on the Wake Field for the Next Linear Collider,” SLAC-PUB8485,Proceedings of the 7th European Particle Accelerator Conference
(EPAC2000), Vienna, Austria, June 2000, p(2000).
S. G. Tantawi,...,N. M. Kroll, et al, “Evaluation of the TE_12 Mode in Circular
Waveguide for Low-Loss High-Power RF Transmission,” Phys. Rev. ST Accel.
Beams 3, 082001 (2000).
J.W. Wang,...,N. Kroll, et al, “Design, Fabrication and Measurement of the First
Rounded Damped Detuned Structure (RDDS),” SLAC-PUB-8583, Proceedings of
the XX International Linac Conference (LINAC2000), Monterey, CA, Aug 2000,
p(2000).
33.
34.
35.
36.
37.
38.
39.
40.
N.M. Kroll, C. K. Ng, and D. C. Vier, “Applications of Time Domain Simulation to
Coupler Design for Periodic Structures,” SLAC-PUB-8614, Proceedings of the XX
International Linac Conference (LINAC2000), Monterey, CA, Aug 2000, p(2000).
R.M. Jones,...,N.M. Kroll, et al, “Comparison of Equivalent Circuit Predictions with
Measurements for Short Stacks of RDDS1 Discs, and their Potential Application to
Improved Wakefield Prediction,” SLAC-PUB-8607, Proceedings of the XX
International Linac Conference (LINAC2000), Monterey, CA, Aug 2000, p(2000)
R.M. Jones, N.M. Kroll, et al, “Local and Fundamental mode Coupler Damping of
the Transverse Wakefield in RDDS1 Linacs,” SLAC-PUB-8608, Proceedings of the
XX International Linac Conference (LINAC2000), Monterey, CA, Aug 2000,
p(2000).
R.M. Jones, N.M. Kroll, et al, “An Investigation of Optimized Frequency
Distributions for Damping Wakefields in X Band Linacs for the NLC,” SLAC-PUB8583, Proceedings of the XX International Linac Conference (LINAC2000),
Monterey, CA, Aug 2000, p(2000).
David R. Smith and Norman Kroll, “Negative Refractive Index in Left Handed
Materials,” Phys. Rev. Lett. 85(14) 2933 (2000).
D. R. Smith, D. C. Smith, N. Kroll, and S. Schultz, “Direct Calculation of
Permeability and Permittivity in a Left-Handed Metamaterial,” Appl. Phys. Lett.
77(14) 2246 2000.
D.T. Palmer,...,N. Kroll, et al, “The Design, Fabrication, and RF Measurement of
the First 25 Cell W-Band Constant Impedance Accelerating Structure,”
Proceedings of the 9'th Workshop on Advanced Accelerator Concepts (AAC2000),
Santa Fe, NM, June 2000, in press
Smith, D.R.,...,Kroll, N., Schultz, S., “Left-Handed Metamaterials,” NATO
Advanced Study Institute on Photonic Crystals and Light Localization, Limin
Hersonissou, Crete, Greece (2000), in press
Norman Kroll (PI)
Physics Department 0319
University of California – San Diego
9500 Gilman Drive
La Jolla, California 92093
PHONE: 858/534-6695
FAX: 858/534-0173
Photonic Band Gap Accelerators and Left-Handed Metamaterials
S. Schultz - University of California, San Diego
Summary:
The Photonic Band Gap Accelerator
Our group first suggested in 1992 that Photonic Band Gap (PBG) resonant structures
would have favorable properties for future lower cost, high gradient, high energy
electron accelerators. It was noted that periodic arrays of scattering elements
possessed unique mode structures, and that cavities based on the PBG geometry would
have novel, and potentially advantageous higher order mode (HOM) properties. Over
the past several years, we have performed extremely detailed finite-difference time and
frequency domain calculations on various model PBG structures, in an effort to fully
characterize and optimize practical designs. We numerically demonstrated a PBG cavity
with a high Q-factor fundamental monopole (accelerating) mode, with every HOM being
damped with peripheral absorber to a Q of less than or on the order of 100. We then
performed a wakefield study, utilizing the computed modes at synchronous frequencies,
which showed that the undamped PBG structure would perform at least as well as, or
better than, a pillbox structure scaled to the same fundamental frequency. However,
the unique modal and physical characteristics of the PBG suggest that it will be superior
with respect to damping, fabrication, and tuning.
Numerical design of coupling units is a very time-consuming and computer intensive
process. However, we have not only recently completed an optimal design for matched
coupling units, but in the process we have developed a new protocol which greatly
increases the efficiency of finding the matched condition. We have thus brought the
design time of accelerating coupling units down considerably.
In conjunction with our PBG project studies, we have also performed numerous
numerical characterization studies on a Zipper cavity structure for potential use at
91GHz. The Zipper is a planar accelerator structure intended to operate at W-band and
whose design is governed by ease of fabrication considerations. Due to an evanescent
band present in the structure, in order to get accurate results, we had to simulate a full
24 cell zipper structure. Using the new numerical coupling procedure, we achieved a
good match with a quarter wave coupler. [For more detail on the Zipper work and the
evanescent band problem, we refer to Professor Kroll's summary report.]
Our PBG coupler design is based on conventional pillbox cavities. Utilizing our new
matching procedure, the radius of the pillbox coupling cavities and the width of the
coupling iris between these cavities and the waveguide were adjusted to numerically
obtain a matched condition to a PBG acceleration unit. In collaboration with the ARD-B
group at SLAC, an 11.424GHz, five cell (excluding coupler cells) version of our PBG
structure has been fabricated. The input and output couplers are in the process of
fabrication. We have shown that individual PBG cells can be tuned by expanding the
diameters of the hollow innermost PBG lattice cylinders. Cold testing of the structure
will commence as soon as construction has been completed. Our program is to continue
this effort, performing the standard evaluation testing (e.g., bead-pull and hot beam
tests), and evolving to an optimized structure at 91 GHz capable of meeting the target
next generation accelerator parameters.
Left-Handed Metamaterials
As an outgrowth of our research on the PBG accelerator project, we performed the first
experimental demonstration of a composite Left-Handed material—a material with the
electric permittivity and magnetic permeability simultaneously negative. We described
this work at an invited press conference at the American Physical Society meeting in
Minneapolis (March 20-24, 2000), and an introductory review appeared in the “Search
and Discovery” section of Physics Today [p12, May 2000], with the original work
reported in Physical Review Letters (Vol. 84, p. 4184, 2000)
The existence of Left-Handed materials had been suggested in 1964 by Soviet physicist
V. G. Veselago, who predicted that if such a material could be found, it would exhibit
very unusual electromagnetic scattering phenomena. In particular, Veselago predicted
that the Doppler shift, Cerenkov radiation and radiation pressure, would be reversed.
Even Snell’s law, which predicts how light “bends” when entering a medium with a
different refractive index, is reversed when the underlying material is Left-Handed,
bending in the opposite direction. The reversal of the refraction properties allows LeftHanded materials to be equivalently thought of as having negative refractive index.
However, until now, the absence of any naturally occurring material with negative
permeability (and without large associated damping) was the reason a Left-Handed
material had never been observed.
We were able to produce a Left-Handed material because of an important discovery by
Professor J. B. Pendry (Imperial College, London), who suggested that certain
configurations of metal scattering elements—split ring resonators (SRRs)—when
grouped together into a closely spaced array, would respond predominantly to the
magnetic field of applied electromagnetic radiation, and thus possess an effective
permeability. Professor Pendry further showed that the dispersion for this assembled
medium could have a frequency band over which the effective permeability was
negative! By combining this structured material with a second medium consisting of
conducting posts, we were able to demonstrate a composite medium having a
frequency band with simultaneously negative permeability and permittivity.
This new composite material, composed entirely of conducting units much smaller than
the wavelengths of interest, fits the definition of a metamaterial. We are currently
investigating Left-Handed metamaterials for novel absorbing materials, optimally
designed for accelerator applications.
Recent Publications
1. Smith, D. R., Vier, D. C., Padilla, W., Nemat-Nasser, S. N., Schultz, S., “Loop wire
medium for investigating plasmons at microwave frequencies,” Appl. Phys. Lett. 75,
1425 (1999).
2. Kroll, N., Schultz, S., Smith, D. R., Vier, D. C., “Photonic band gap accelerator cavity
design at 90 GHz,” Proceedings of the Particle Accelerator Conference, 2, 830, New
York (1999).
3. Kroll, N. M., Hill, M. E., Lin, X. E., Siemann, R. H., Vier, D. C., Whittum, D. H.,
Palmer, D. T., “Planar accelerator structures for millimeter wavelengths,”
Proceedings of the 1999 Particle Accelerator Conference, New York, 3612 (1999).
4. Smith, D. R., Willie J. Padilla, Vier, D. C., Nemat-Nasser, S. C., Schultz, S., “A
composite medium with simultaneously negative permeability and permittivity,”
Phys. Rev. Lett., 84, 4184 (2000).
5. Smith, D. R., Kroll, N., “Negative refractive index in left-handed materials,” Phys.
Rev. Lett., 85, 2933 (2000).
6. Smith, D. R., Vier, D. C., Kroll, N., Schultz, S., “Direct calculation of permeability and
permittivity for a left-handed metamaterial,” Appl. Phys. Lett., 77, 2246 (2000).
7. Smith, D. R., Padilla, W. J., Vier, D. C., Shelby, R., Nemat-Nasser, S. C., Kroll, N.,
Schultz, S., “Left-handed metamaterials,” NATO Advanced Study Institute on
Photonic Crystals and Light Localization, Limin Hersonissou, Crete, Greece (2000), in
press.
8. Kroll, N. M., Ng, C.-K., Vier, D. C., “Applications of time domain simulation to coupler
design for periodic structures,” Presented at Linac2000 (2000).
Current Staff:
S. Schultz
N. Kroll
D.C. Vier
D.R. Smith
Co-PI
Scientist
Scientist
Sheldon Schultz (PI)
Physics Department 0319
University of California – San Diego
9500 Gilman Drive
La Jolla, California 92093
PHONE: 858/534-4078
FAX: 858/534-0173
Chaotic Dynamics in Accelerator Physics
J.R. Cary, University of Colorado
Summary:
Our group does research on chaotic dynamics in accelerator physics, reduced models of
self-consistent beam dynamics, and computational modeling of advanced acceleration
concepts and intense particle beams.
One outcome of our work was the development and implementation of a resonance
elimination method for increasing dynamic aperture in accelerator lattices. Our
application to the lattice of the Advanced Light Source showed that one can increase
the 4D volume of confined phase-space by a factor of nearly eight. Future directions
include finding the optimal parameters for improving the dynamic aperture and
determining the sensitivity of our solutions.
We also developed the nonlinear theory of the interaction of a beam with a cavity
mode. Our work showed that the beam decelerates and simultaneously decreases the
cavity mode frequency. This corresponds to a frequency chirping, as has been
observed in experiment.
In recent years we have moved towards computational modeling of accelerator
systems. In collaboration with Tech-X Corporation, the Lawrence Berkeley Laboratory,
and the University of California at Berkeley, we have adapted the XOOPIC Particle-InCell (PIC) plasma simulation code to simulations of advanced acceleration concepts.
The XOOPIC plasma simulation code was originally used for microwave tube
simulations. We adapted it to the study of advanced acceleration concepts by adding
laser pulse launchers of arbitrary convergence and from any boundary and adding the
capability of doing moving window simulations for parallel computations. Further, our
tests proved to be particularly demanding, as they exercised implementation problems
that were ultimately fixed as part of this collaboration.
With these adaptations we are able to carry out simulations of Laser-Wake-Field
Acceleration (LWFA) experiments. Our comparisons with the fluid simulations of LBNL
have been successful. The results of the two codes are in agreement in the regime
where both are valid. Thus, we successfully predict the laser wake field.
We are now simulating colliding pulse systems, which were proposed as a method for
injecting particles into the accelerated region of phase space by Esarey et al. This
mechanism relies on concepts (e.g., island overlap) of chaotic dynamics. The overlap
of the island induced by the beat wave of the colliding pulses with the island of the
accelerating potential causes a transfer of some particles to the acceleration region.
We have observed the potentials in our system, and we are now carrying out parameter
studies.
Two other directions we mention in passing only. One is the study of cold charged
particle systems. These systems are found in laser cooled beams, and they are used as
targets for high-energy physics experiments. We are investigating phase transitions in
such systems, to see whether ultracold systems can be obtained. A second area of
pursuit is the understanding of beam halos. Our goal here is to understand whether
halo formation can be suppressed by the use of nonlinear lattices, as we have found to
exist earlier in our research program.
Recent results of our research
• Development and implementation of a method to decrease the effect of
resonances with the ultimate consequence of increasing dynamics aperture
• Elucidation of object oriented programming principles for accelerator modeling
• Development of a reduced description of the deceleration of a coasting beam
interaction with a cavity mode
• Adapted parallel code OOPIC to simulation of Laser-Wake-Field Acceleration
• First PIC simulations of counter-propagating pulses for injection of particles into
the accelerating potential produced by laser-plasma interactions
Publications:
Refereed Journal Articles
1.
2.
3.
4.
5.
D. L. Bruhwiler, R. Giacone, J. R. Cary, J. P. Verboncoeur, P. Mardahl, E. Esarey
and W. P. Leeman, “Particle-in-Cell Simulations of Plasma Accelerators and
Electron-Neutral Collisions,” Phys. Rev. ST/AB, submitted (2000).
W. Wan and J. R. Cary, “Finding Four Dimensional Symplectic Maps with Reduced
Chaos,” Phys. Rev. ST/AB, submitted (2000).
P. H. Stoltz and J. R. Cary, "Nonlinear theory of beam bunching and deceleration
due to cavity damping," Physics of Plasma 7 (1), 231-242 (2000).
David L. Bruhwiler, Svetlana G. Shasharina and John R. Cary, “The OptSolve++
Software Components for Nonlinear Optimization and Root Finding,” Computing in
Object Oriented Parallel Environments, Lecture Notes in Computer Science 1732,
154-163 (1999).
Weishi Wan and John R. Cary, " Increasing the dynamic aperture of accelerator
lattices," Phys. Rev. Lett. 81, 3655 (1998).
Conference Proceedings and invited talks
6.
7.
8.
K. Sonnad, J. R. Cary, and R. Giacone, “Halo formation in and intense charged
particle beam,” paper MOP5B07, Proc. European Particle Accelerator Conference,
2000 (available at
http://accelconf.web.cern.ch/accelconf/e00/PAPERS/MOP5B07.pdf).
J. Lee and J. R. Cary, “Numerical solutions of a crystallized non-neutral plasma,”
paper MOP5B06, Proc. European Particle Accelerator Conference, 2000 (available
at http://accelconf.web.cern.ch/accelconf/e00/PAPERS/MOP5B06.pdf).
R. Giacone, J. R. Cary, D. Bruhwiler, P. Mardahl, and J. P. Verboncoeur,
“Simulations of pulse propagation in the laser wakefield accelerator using a
massively-parallel object-oriented particle-in-cell code,” paper THP2B05, Proc.
European Particle Accelerator Conference, 2000 (available at
http://accelconf.web.cern.ch/accelconf/e00/PAPERS/THP2B05.pdf).
9.
10.
11.
12.
S. G..Shasharina, J. R. Cary, “Nonlinear optimization in the C++ beam optics
code,” paper TUP6A08, Proc. European Particle Accelerator Conference, 2000
(available at http://accelconf.web.cern.ch/accelconf/e00/PAPERS/TUP6A08.pdf).
D. Bruhwiler, J. Cary, J. Verboncoeur, P. Mardahl, R. Giacone, “Simulations of
plasma wakefield acceleration with XOOPIC,” paper THP2B04, Proc. European
Particle Accelerator Conference, 2000 (available at
http://accelconf.web.cern.ch/accelconf/e00/PAPERS/THP2B04.pdf).
S. G. Shasharina and J. R. Cary, “Efficient differential algebra computations,”
Proc. 1999 Particle Accelerator Conference, p. 20 (New York City, NY, 1999).
D. L. Bruhwiler, J. R. Cary, S. G. Shasharina, “Object Oriented C++ Software
Components for Accelerator Design,” Proc. 1999 Particle Accelerator Conference,
p. 20 (New York City, NY, 1999).
Conference Presentations
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
D. Bruhwiler, P. Chen, J. Ng, W. Leemans, E. Esarey, J. R. Cary, R. Giacone,, J.
Verboncoeur, P. Mardahl, “PIC Simulations of Beam-Induced Ionization in Recent
Plasma Lens Experiments,” paper BO2.003, Bull. Am. Phys. Soc. 45 (7), 27
(2000).
K. Sonnad, J. R. Cary, “The influence of nonlinear terms to external focusing on
beam halo formation,” paper DP1.060, Bull. Am. Phys. Soc. 45 (7), 103 (2000).
J. Lee, J. R. Cary, “Numerical Simulations of A Crystallized Non-neutral Plasma,”
paper UP1.016, Bull. Am. Phys. Soc. 45 (7), 16 (2000).
R. E. Giacone, J. R. Cary, B. A. Shadwick, E. Esarey, W. P. Leemans, D. Bruhwiler,
P. Mardahl, J. P. Verboncoeur, “Comparison of PIC and fluid simulations for pulse
propagation in the laser wake field accelerator,” paper UP1.049, Bull. Am. Phys.
Soc. 45 (7), 308 (2000).
Svetlana G. Shasharina and John R. Cary, “An Improved Levenberg-Marquardt
Solver for Multiple-Target Optimization,” Bull. Am. Phys. Soc. 44 (7), 82 (1999).
Jinhyung Lee and John R. Cary, “Molecular Dynamics of a Strongly Magnetized
Non-Neutral Plasma,” Bull. Am. Phys. Soc. 44 (7), 106 (1999).
K. Sonnad, John R. Cary, and R. Giacone, “Study of beam confinement and
emittance growth in and intense charged particle beam using PIC simulations,”
Bull. Am. Phys. Soc. 44 (7), 203 (1999).
D. Bruhwiler, K. Luetkemeyer, and John R. Cary, “Cross-Platform Graphical User
Interface with fast 3D Rendering for Particle-In-Cell Simulations,” Bull. Am. Phys.
Soc. 44 (7), 252 (1999).
R. Giacone, J. Cary, and K. Sonnad, “Simulations of pulse propagation in the laser
wakefield accelerator using an object-oriented particle in cell code,” Bull. Am.
Phys. Soc. 44 (7), 297 (1999).
J. Lee, J. R. Cary, “Calculation of finite-length, hollow-beam equilibria,” Proc.
1999 Particle Accelerator Conference, p. 174 (New York City, NY, 1999).
Current Staff:
•
•
•
•
•
•
Cary, J. R.
Giacone, R.
Lee,J.
Sonnad, K.
James, C.
Przebinda, V.
PI
Research Associate (postdoc)
Graduate Student
Graduate Student
Professional Research Assistant
Undergraduate Student (system adminstration)
John R. Cary
Center for Integrated Plasma Studies and Department of Physics
University of Colorado
BOULDER, CO 80309-0390
PHONE:
FAX:
E-MAIL:
Website:
303/492-1489
303/492-0642
[email protected]
http://www-beams.colorado.edu/
Recent Research Illustrations
Figure 1: Improvement of dynamic aperture through resonance cancelling. Dynamic
aperture of the Advanced Light Source before improvement by resonance elimination.
Dynamic aperture of the Advanced Light Source after improvement by resonance
elimination.
Longitudinal Electric field produced by an intense, short laser pulse.
Develop Nonlinear Correction Strategies
For LHC Interaction Regions
Summary:
J. Shi - The University of Kansas
During the past year, we have been collaborating with the US-LHC Project to develop
nonlinear correction strategies for LHC interaction regions (IRs) . We have also been
studying the strong-strong beam-beam effects in hadron colliders. Three topics have
been pursued.
1. Global Compensation of Nonlinear Field Errors
In conventional magnet corrections, systematic field errors are compensated with
correctors placed nearby the source of errors. It is, however, difficult to correct random
errors as well as high-order systematic errors on individual magnets. The global
compensation of the field errors based on the minimization of nonlinearities in one-turn
maps has thus been developed as an alternative for reducing the detrimental effects of
both the systematic and random errors. Our study on the LHC collision lattice showed
that this global compensation is effective and flexible. Compared to the local corrections
of the field errors, the global correction has several advantages. (a) The random errors
of large number of magnets can be compensated with a few groups of
independent-powered correctors. (b) Since the low-order nonlinear terms of the map
usually dominate beam dynamics, only low-order correctors are needed for the global
correction even though high-order multipoles may be important to beam dynamics due
to feed-down effects. (c) The global correction of the nonlinear fields may be further
optimized with direct measurements of one-turn maps in beam-dynamics experiments
during the operation of a storage ring.
2. Study of Self Compensation of Random Field Errors in LHC IRs
The field errors of superconducting quadrupoles in LHC IRs are one of the major causes
for limiting the dynamic aperture of LHC during collisions. Sorting of the quadrupoles, in
which the magnets are installed in a sequence based on field measurements, is a way
to reduce adverse effects of random field errors. Because of a very small phase advance
within each triplet, significant self-compensation of the field errors can be achieved
even with sorting of a small number of quadrupoles. Our study showed that the vector
sorting scheme is very effective in generating a magnet arrangement in which the
random errors among the quadrupoles of each triplet are well compensated. Since this
sorting scheme is based entirely on the local compensation of random errors in each
triplet, the effectiveness of the sorting is robust to the change of operational conditions
of the collider.
3. Study of Strong-Strong Beam-Beam Effects in Hadron Colliders
We developed a fully self-consistent tracking code based on the method of the
particle-in-cell for studying beam-beam effects in hadron colliders. The strong-strong
beam-beam effects of hadron beams were studied on LHC including multipole field
errors in the lattice and beam-beam interactions at two high-luminosity interaction
points. It was found that the beam-beam interaction could result in two distinct
dynamics for hadron beams: a slow beam-size growth and a spontaneous unstable
beam-centroid oscillation. The instability of the beam centroid oscillation has typical
characteristics of the chaotic transport; i.e. the amplitude increase of the oscillation
consists of slow escape from the remnants of invariant manifolds and fast diffusion in
fully developed chaotic regions. The simulation results indicate that there is a threshold
of the beam-beam parameter for the beam-beam instability. Below that threshold, no
unstable beam-centroid motion was observed. After the onset of the beam-beam
instability, particles in beam cores cross low-order resonances, which results in the
enhanced beam-size growth. The growth rate of beam sizes increases with the
oscillation amplitude of beam centroids. The study showed that much of the
beam-beam instability could be effectively suppressed by an elimination of the centroid
motion with feedback.
Publications:
1. J. Shi, "Global Correction of Magnetic Field Errors in LHC Interaction Regions", to
appear on Particle Accelerators (2000).
2. J. Shi and D. Yao, "Collective Beam-Beam Effects in Hadron Colliders", Phys. Rev.
E62, 1258 (2000).
3. J. Shi, "Global Compensation of Magnetic Field Errors with Minimization of Nonlinearities in Poincaré Map of a Circular Accelerator", A444, 534 (2000).
4. J. Shi, "Self Compensation of Random Field Errors in Low-β Insertion Triplets of
Large Hadron Colliders", Nucl. Instr. & Meth. A430, 24 (1999).
5. J. Shi, "Sorting of High-Gradient Quadrupoles in LHC Interaction Regions", in Proc.
of the Workshop on LHC Interaction Region Correction Systems and Brookhaven
National Laboratory Formal Report BNL-52575, (1999).
6. J. Shi, "Global Compensation of Nonlinear Fields in LHC", in Proc. of the Workshop
on LHC Interaction Region Correction Systems and Brookhaven National Laboratory
Formal Report BNL-52575, (1999).
7. J. Shi and P. Suwannakoon, "Single-particle dynamics in particle storage rings with
integral polynomial factorization maps", Phys. Rev. E58, (1998).
8. D. Yao and J. Shi , “Method of Projection Operator for the Study of Angle Averaged
Distribution Function of Beam Particles in Hadron Storage Rings,” Phys. Rev.
ST-AB1, 84001 (1998).
9. J. Shi and S. Ohnuma, "Sorting of Magnets in Large Superconducting
Synchrotrons", Particle Accelerators 56, 227 (1997).
Current Staff:
•
•
•
Jack Shi
Orathai Kheawpum
Lihui Jin
JiCong (Jack) Shi (PI)
Department of Physics and Astronomy
University of Kansas
Lawrence, Kansas 66045
PHONE: (785) 864-5273
P.I.
Ph.D. Graduate Student
Ph.D. Graduate Student
Dynamical Systems and Accelerator Theory Group
Professors Alex J. Dragt and Robert L. Gluckstern- University of Maryland
Summary:
The University of Maryland Group has been carrying out long-term research work in the
general area of Dynamical Systems with a particular emphasis on applications to
Accelerator Physics. This work is broadly divided into two tasks:
•
The Computation of Charged Particle Beam Transport,
•
The Computation of Electromagnetic Fields and Beam-Cavity Interactions.
Each of these tasks is described briefly below. Work is devoted both to the development
of new methods and the application of these methods to problems of current interest in
accelerator physics including the theoretical performance of present and proposed high
energy machines.
Task A: Computation of Charged Particle Beam Transport
Overview
New methods, employing Lie algebraic tools, have been developed for the computation
of charged particle beam transport and accelerator design. These methods have been
used for the design of the SLAC B factory and for final focus systems in the SLAC Test
Beam Facility and the NLC, and are being used in the design of the LHC, and in the
design of high current accelerators for neutron spallation sources, neutrino factories,
and muon colliders. They are also being used at LANL both for multimillion
macroparticle intense beam simulations and proton radiography studies. This work is
documented in the book "Lie Methods for Nonlinear Dynamics with Applications to
Accelerator Physics" that is in draft form (725 pages currently written) and in the
"MaryLie 3.0 User's Manual, A Program for Charged Particle Beam Transport Based on
Lie Algebraic Methods" (750 pages). Copies of these documents are available upon
request. Our goal is to provide a comprehensive treatment of the nonlinear (as well as
fully coupled linear) behavior of charged particle orbits in both single pass and
circulating machines.
Current work
(A1) We have obtained a symplectic group-theoretical classification of general analytic
vector fields and have discovered how to decompose them uniquely into Hamiltonian
and non-Hamiltonian parts. This approach also provides a unique factorization of
general analytic maps into symplectic and non-symplectic parts. Thus, there is now a
complete Lie framework for treating non-Hamiltonian as well as Hamiltonian systems.
This work is believed to be a fundamental new Dynamical Systems result. With regard
to Accelerator Physics, this work should facilitate the Map and Lie treatment of
synchrotron radiation damping. This result is described in Chapter 17 (some 50 pages)
of the book "Lie Methods for Nonlinear Dynamics with Applications to Accelerator
Physics" referenced above. A manuscript is also currently in preparation.
(A2) The classical limit of and quantum corrections to charged-particle motion in
electromagnetic fields should be derivable from first-principle calculation using QED and
Feynman diagrams. With these methods, we are able to describe the evolution of
relativistic wave packets including the case of photon emission. We intend to make a
systematic exploration of quantum effects for particle beams including the quantum
analog of Lorentz-Dirac radiation reaction and its connection to quantum corrected
synchrotron radiation, nonlocal forces arising from extended wavepackets in
inhomogeneous fields, spin effects including magnetic moments and spin polarization,
quantum excitation and damping, and higher order quantum corrections. A preliminary
report on this work will be presented at the ICFA Quantum Aspects of Beam Physics
2000 Conference.
(A3) A transfer map can describe the passage of a charged particle through a region of
nonvanishing electromagnetic fields (e.g., a bending magnet, multipole magnet,
spectrometer, electrostatic lens, electromagnetic velocity separator, etc.). This map can
be represented in either Taylor or Lie form. Calculation of aberration terms (terms
beyond first order) in the map requires knowledge of multiple derivatives of the
electromagnetic fields along a reference trajectory through the region. For general
geometries, three-dimensional field distributions in the region are presently obtained
only by measurement or by numerical solution of the boundary-value problems for the
electromagnetic fields. Any attempt to differentiate such field data multiple times is
soon dominated by "noise" due to finite meshing and/or measurement errors. We have
solved this fundamental problem by the use of field data on a surface outside of the
reference trajectory to reconstruct the fields along and around the reference trajectory.
The vector and scalar potentials and their multiple derivatives (required for a
Hamiltonian map integration) are shown to be calculable from boundary data with the
aid of Helmholtz's theorem and a novel application of the Dirac monopole vector
potential. Using these methods, modules can be added to existing electromagnetic
codes that will produce reliably, when requested, associated transfer maps to any order
for arbitrary static charged-particle beamline elements. Thus it is now possible, for the
first time, to design and analyze the effect of general static beam-line elements,
including all fringe-field and error effects, in complete detail. This work, carried out in
collaboration with P. Walstrom of LANL, will be presented at the International
Computational Accelerator Physics 2000 Conference.
Task B: Computation of Electromagnetic Fields and Beam-Cavity Interactions
Current Work
(B1) Over the past 7 years the University of Maryland group has made important
contributions to the understanding of halo formation in high current linac beams. These
same methods are now being applied to the understanding of possible halo formation
and other resonant effects in circular accelerators, with particular attention to the
Spallation Neutron Source (SNS) rings being designed at BNL. This work is being
carried out in collaboration with A. Fedotov, a former Maryland graduate student and
post-doc who is now on the SNS staff at BNL.
(B2) A second area of continued work is the study of coupling impedances in beam
pipes and its importance in understanding beam current limitations in circular
accelerators. Present activities include the calculation of the shielding of beams from
obstacles in the beam pipe such as pump ports, beam position monitors, kickers, etc. by
metallic wires or strips mounted on a ceramic pipe. This work is being carried out in
collaboration with T.S. Wang at LANL and B. Zotter at CERN, and is relevant to
measurements now taking place at CERN.
(B3) A third area of recent activity is a study of the evolution of a mismatched
spherically symmetric beam bunch in a focussing channel using the Vlasov equation
supplemented by the Boltzmann equation to include intra-beam collisions. The purpose
of the work is to understand a variety of mismatched collective modes as well as the
details of the approach to thermal equilibrium. This work is being carried out in
collaboration with R. Ryne and J. Qiang at LANL.
Publications over the past 3 years
Task A:
1. A.J. Dragt and M. Venturini, “ACCURATE COMPUTATION OF TRANSFER MAPS FROM
MAGNETIC FIELD DATA,” Nucl. Instr. Meth. A (1998).
2. G. Gillespie, M. Lampel, and A.J. Dragt, “A MULTI-PLATFORM GRAPHIC USER
INTERFACE FOR THE PARTICLE OPTICS CODE MARYLIE,” Proceedings of the
Chicago Linear Accelerator Conference (1998).
3. G. Gillespie, M. Lampel, and A.J. Dragt, “MULTI-PLATFORM GRAPHIC USER
INTERFACE FOR THE MARYLIE CHARGED PARTICLE BEAM TRANSPORT CODE,”
Proceedings of the 1998 International Computational Accelerator Physics Conference
(1998).
4. A.J. Dragt, M. Venturini, and D. Abell, “COMPUTATION OF EXACT TRANSFER MAPS
FOR LHC HIGH-GRADIENT QUADRUPOLES AND LHC DYNAMIC APERTURE,”
Proceedings of the 1998 International Computational Accelerator Physics Conference
(1998).
5. A.J. Dragt and S. Habib, “BEHAVIOR OF WIGNER FUNCTIONS UNDER
ABERRATIONS,” Proceedings of the ICFA Quantum Aspects of Beam Physics 1998
Conference (1999).
6. G. Gillespie, M. Lampel, and A.J. Dragt, “USING MARYLIE WITH THE PARTICLE
BEAM OPTICS LABORATORY,” Proceedings of the New York Particle Accelerator
Conference (1999).
7. A.J. Dragt, M. Venturini, and D. Abell, “MAP COMPUTATION FROM MAGNETIC FIELD
DATA WITH APPLICATIONS TO THE LHC HIGH GRADIENT QUADRUPOLES,”
Proceedings of the New York Particle Accelerator Conference (1999).
8. A.J. Dragt and M. Venturini, “COMPUTING TRANSFER MAPS FROM MAGNETIC FIELD
DATA,” Proceedings of the New York Particle Accelerator Conference (1999).
9. M. Venturini, “SCALING OF THIRD-ORDER QUADRUPOLE ABERRATIONS WITH
FRINGE FIELD EXTENSION,” Proceedings of the New York Particle Accelerator
Conference (1999).
10. A.J. Dragt, “RELEASE OF MARYLIE 3.0,” Proceedings of the New York Particle
Accelerator Conference (1999).
11. A.J. Dragt and J. Irwin, “TAYLOR MAPS,” Handbook of Accelerator Physics and
Engineering, A. Chao and M. Tigner, Editors, World Scientific (1999).
12. A.J. Dragt, “LIE MAPS,” Handbook of Accelerator Physics and Engineering, A. Chao
and M. Tigner, Editors, World Scientific (1999).
13. With regard to item A3 above, P. Roberts, a past graduate student in the group, has
written a scholarly paper on the work to satisfy M.S. degree requirements. Copies
are available upon request.
Task B:
1. R.L. Gluckstern, J. Murphy, and S. Krinsky, “LONGITUDINAL WAKEFIELD FOR AN
ELECTRON MOVING ON A CIRCULAR ORBIT,” Particle Accelerators Vol. 57, 9
(1997).
2. R.L. Gluckstern and A.V. Fedotov, “ANALYTIC AND NUMERICAL ANALYSIS OF THE
LONGITUDINAL COULPING IMPEDANCE OF A RECTANGULAR SLOT IN A THIN
COAXIAL LINER,” Phys. Rev. E, Vol. 56, 3583 (1997).
3. R.L. Gluckstern and A.V. Fedotov, “IMPEDANCE AND RESONANCE ISSUES FOR A
LONG RECTANGULAR SLOT IN A COAXIAL LINER,” Phys. Rev. E, Vol. 56,7217
(1997).
4. R.L. Gluckstern, A.V. Fedotov, S.S. Kurennoy, and R.D. Ryne, “LONGITUDINAL
HALO IN BEAM BUNCHES WITH SELF-CONSISTENT 6-D DISTRIBUTIONS,”
Proceedings of Workshop on Space Charge, Long Island, NY (May 1998).
5. A.V. Fedotov, R.L. Gluckstern, S.S. Kurennoy, and R.D. Ryne, “HALO FORMATION IN
SPHEROIDAL BUNCHES WITH SELF-CONSISTENT STATIONARY DISTRIBUTIONS,”
Proceedings of the European Accelerator Conference (June 1998).
6. A.V. Fedotov and R.L. Gluckstern, “ANALYSIS OF THE FREQUENCY DEPENDENCE OF
THE LONGITUDINAL COUPLING IMPEDANCE OF A SMALL HOLE IN A COAXIAL
LINER,” Proceedings of the Chicago Linear Accelerator Conference (August 1998).
3-D BUNCHES WITH DIFFERENT PHASE SPACE DISTRIBUTIONS,” Proceedings of
the Chicago Linear Accelerator Conference (August 1998).
8. R.L. Gluckstern, A.V. Fedotov, S.S. Kurennoy, and R.D. Ryne, “HALO FORMATION IN
3-D BUNCHES,” Phys. Rev. E, Vol. 58, 4977, (1998).
9. A.V. Fedotov and R.L. Gluckstern, “LONGITUDINAL COUPLING IMPEDANCE OF A
SMALL HOLE IN A COAXIAL LINER NEAR THE CUTOFF FREQUENCIES,” Phys. Rev.
ST Accel. Beams 1, 024401, (1998).
3-D BUNCHES WITH DIFFERENT PHASE SPACE DISTRIBUTIONS,” Phys. Rev. ST
Accel. Beams 1, 01420, (1999).
11. A.V. Fedotov and R.L. Gluckstern, “HALO FORMATION IN INTENSE BUNCHED
BEAMS,” Proceedings of the New York Particle Accelerator Conference, (Invited
Paper) (March 1999).
12. T. S. Wang and R.L. Gluckstern, “IMPEDANCE OF RF SHIELDING WIRES,”
Proceedings of the New York Particle Accelerator Conference, (March 1999).
13. R.L. Gluckstern and A.V. Fedotov, “HALO FORMATION IN HIGH INTENSITY
LINACS,” Proceedings of the 7th ICFA Mini Workshop on High Intensity High
Brightness Hadron Beams, Lake Geneva, WI, (September 1999).
14. R.L. Gluckstern and A.V. Fedotov, “COULOMB SCATTERING WITHIN A SPHERICAL
BUNCH IN A HIGH CURRENT LINEAR ACCELERATOR,” Phys. Rev. ST Accel. Beams
2, 054201 (1999).
15. A.V. Fedotov and R.L. Gluckstern, “COULOMB SCATTERING WITHIN A SPHERICAL
BUNCH IN HIGH CURRENT LINEAR ACCELERATORS,” Proceedings of the New York
Particle Accelerator Conference, (March 1999).
16. A.V. Fedotov, R.L. Gluckstern, and M. Venturini, “TRANSVERSE IMPEDANCE OF A
PERIODIC ARRAY OF CAVITIES,” Phys. Rev. ST Accel. Beams 2, 06440 (1999).
17. A.V. Fedotov, R.L. Gluckstern, and M. Venturini, “HIGH FREQUENCY BEHAVIOR OF
TRANSVERSE IMPEDANCE FOR A CAVITY IN A BEAM PIPE,” Proceedings of the New
York Particle Accelerator Conference, (March 1999).
18. With regard to item B2 above, R. Gluckstern gave a one week course on Analytic
Methods for the Calculation of Coupling Impedances at the January 2000 Particle
Accelerator School held at Tucson, AZ. The lecture notes prepared for the course
are being published as a CERN report, and copies are available upon request. They
specifically address the shielding of coupling impedance by conducting wires and
strips mounted on ceramic. In addition a paper on coupling impedances with
applications to present and planned accelerators is being prepared in collaboration
with B. Zotter at CERN.
19. With regard to item B3 above, the work is still in preliminary form. M. Williams, a
past graduate student in the group, has written a scholarly paper on the work to
satisfy M.S. degree requirements. Copies are available upon request.
Graphics
MaryLie Simulation of Beam Line for Proton Radiography
Wire Shielding of LHC Beam
Present Staff:
Alex Dragt
Howard Gluckstern
Philip Johnson
David Fiske
Timothy Stasevich
Aaron Bodoh-Creed
PI
PI
Postdoctoral Research Associate
Graduate Student
Graduate Student
Alex J. Dragt (PI)
University of Maryland
Room 3124C, Physics Building
College Park, Maryland 20742-4111
PHONE: 301-405-6053
WEB: http://www.physics.umd.edu/dsat/
Fourier plane
Object
IL1
Diffuser
Illuminating and Scattered Rays [cm]
IL0
Fourier plane
MaryLie Simulation of Beam Line for Proton Radiography
Illuminator
Beam Monitor Lens
Image Lens 1
Image Lens 2
Pathlength [m]
* Illuminator spreads rays scattered by diffuser to
cover object, while providing achromatic correlation.
* Monitor lens copies phase space distibution
observed at IL0 onto object.
Object MCS Angle
15 mR
10 mR
5 mR
0 mR
* Angle cut collimators are placed at Fourier planes,
where rays are sorted by object MCS angle.
Wire Shielding
of LHC Beam
IL2
Accelerator Research Studies – Task A
H. Milchberg and T. Antonsen – University of Maryland
Summary:
(a) Experiment
Our discovery and development of the laser-produced plasma waveguide has made
possible the stable optical guiding of arbitrarily high intensity laser pulses over long
distances in plasmas, greatly exceeding the Rayleigh length, the scale length for
diffraction or transverse spreading of the beam in vacuum. The guiding of high intensity
pulses is essential to laser-driven plasma accelerators. We have made fundamental
contributions in all aspects of the physics relating to waveguide formation and its use
for optical guiding. Over the time of our DOE support (1997-present), we have:
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fully characterized the time and space evolution of the plasma waveguide:
Using picosecond-in-time, µm-in-space resolution interferometry, we measured the
laser-driven generation and hydrodynamic evolution of the plasma waveguide. We
showed that at later times, it evolves like a self-similar cylindrical blast wave. We
found that the plasma evolution closely followed what had been predicted from our
extensive laser-driven hydrodynamics calculations. Of special importance for laserbased accelerator development, we found that the waveguide is axially uniform to a
high degree, supporting the use of moderate length 100ps pulses to generate the
waveguide. This work was published as Phys. Rev. Lett. 78, 2373 (1997).
explored alternative coupling schemes: The plasma waveguide walls are
electron density barriers of finite height, and therefore, under certain conditions,
light can tunnel radially out of the guide or ‘leak’ as Cerenkov-like emission. We
have experimentally explored the inverse of this process, the coupling of sideinjected conical waves to selected modes. This is a possible alternative to traditional
end coupling, and it is mode and frequency selective, offering the possibility of
control of the group velocity of a waveguide mode. Additionally, this was the first
ever demonstration of side coupling to a cylindrical optical fiber of any kind. Phys.
Rev. Lett. 81, 357 (1998).
performed the first guiding of intense femtosecond pulses in plasma
waveguides: Our synchronization of two separate laser systems (Nd:YAG laser100 ps waveguide generation pulses) and the Ti:Sapphire laser (source of
femtosecond pulses)) allowed the first ever experiments in femtosecond plasma
guiding. In these experiments, the waveguide was generated in ambient backfill
gas. At this stage of development of our Ti:Sapphire laser, there was one stage of
amplification after the regenerative amplifier, with a maximum output of 15 mJ.
Maximum coupling efficiency of 30% was measured, with guided intensity of 5x1015
W/cm2 . This was to be compared with efficiencies of 75-80% in lower intensity
experiments. With the FROG (frequency resolved optical gating) diagnostic
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monitoring the plasma waveguide output, we determined that the reduced efficiency
was a result of ionization-induced refraction at the channel entrance. Opt. Lett. 22,
1787 (1997).
demonstrated distortion-free guiding of terawatt level laser pulses in
plasma waveguides produced in gas jets: After a laser energy upgrade, we
demonstrated guided powers of almost 0.4 terawatts (almost 1017W/cm2) over a 1.5
cm long waveguide produced in a pulsed gas jet, at 52% coupling efficiency into the
lowest order mode (Phys. Rev. E 59, R3839 (1999)). This was a factor of over 20
times the guided intensity achieved with channels generated in a gas backfill
(described in #3 above). The gas jet work was earlier presented in Applied Physics
Letters 73, 3064 (1998). Since the waveguide plasma was ionized to stable Ar8+,
there was no further ionization of the waveguide plasma by the guided pulse, and
FROG measurements reveal no distortion of the pulse. It should be noted for
comparison that coupling efficiency of low power laser beams to the fundamental
mode of ordinary glass fibers is typically 50-60%! The guided mode size was larger
than the vacuum spot size, primarily because the channel end is more tapered than
in the backfill case, and longer channel expansion times were necessary for
injection. The naturally occurring drop-off in neutral gas density at the edge of the
jet results in less heating there, so there is less ionization and less channel
expansion. Our current experiments are addressing this coupling issue. The
experimental setup is shown in Figure (a).
performed measurements of pulse shortening resulting from ionizationinduced refraction: Ionization-induced refraction is an important consideration in
the coupling of intense pulses to plasma waveguides (see item #3 above). In order
to more fully understand the phenomenon, we studied this phenomenon using short
helium and argon gas jets. Our FROG (frequency-resolved optical gating) diagnostic
was modified to allow measurements of ionization-induced refraction and time
retardation of intense pulses. Retardation resulted from the body of the pulse
slowing down in the plasma generated by the front of the pulse (since the group
velocity in plasma is less than c). Our wave propagation simulations (T. Antonsen)
agreed well with experiment. (Optics Communications 157, 139 (1998)).
observed and characterized the ionization scattering instability: Under
certain general conditions, ionization-induced scattering, a major issue in coupling to
the plasma waveguide, proceeds as an instability with the development of fine
spatial structure in the electron density. This was predicted by T. Antonsen (Phys
Rev. Lett 82, 3617 (1999)) to be a major pulse degradation mechanism. A paper
describing the results of our experiment verifying this process has been submitted to
Phys. Rev. Lett. (2000).
demonstrated laser-driven implosion of a cylindrical waveguide plasma:
These experiments showed that the application of multiple heating pulses to the
plasma waveguide can result in guided mode control through the laser-driven
concentric compression electron density profile. (Phys. Rev. E 57, 3417 (1998)).
discovered resonantly enhanced generation of plasma waveguides: Plasma
channel generation can take place through a resonant coupling process involving
•
•
self-trapping of the axicon beam (which is a J0 Bessel beam), where the channel
generation and heating can proceed with significantly lower laser energy
requirements. Complete experiments and simulations were published in Phys. Rev.
Lett. 84, 3085 (2000). A case of resonant coupling is shown in Fig. (b).
explored broadband end-coupling of laser pulses to the plasma
waveguide: using the same continuum source as employed in item #2 above, we
have examined the mode structure of the waveguide when injection is from the end.
Together with the results of #1 and #2, this constitutes essentially full
understanding of the linear optics of the plasma waveguide. Phys. Rev. E 61, 1954
(2000). The linear regime is not as restrictive a condition as one might think: the
results of #4 indicate distortion-free propagation up to 1017 W/cm2- there is no
further ionization of the waveguide plasma at that intensity, and relativistic effects
have not yet become significant.
generated a ~ 1 cm long plasma waveguide with a hollow J5 Bessel beam.
In all of our previous work, waveguides were generated using a J0 beam (zero-order
Bessel beam) with an intensity maximum on axis. That method required several
nanoseconds of hydrodynamic shock expansion after the pump pulse to establish
the on-axis electron density minimum. The new method establishes the waveguide
structure promptly during the pump pulse, allowing much smaller waveguide core
diameters (here < 4µm as opposed to ~20-30µm in our previous work), so that
much smaller spot sizes can be guided. Submitted to Phys. Rev. E, Rapid
Communications (2000). Figures (c)and (d) show the J5 beam focus and generated
plasma waveguide.
(b) Theory
The main theoretical effort during the past two years has been the modification of the
code (WAKE) originally developed in collaboration with Ecole Polytechnique, and the use
of this code to simulate laser pulse propagation in regimes relevant to ongoing
experiments at Maryland and elsewhere. New features that have been incorporated into
the code are the following. 1. The ability to simulate laser propagation in channels with
specified radial and axial profiles. 2. The inclusion of a fluid model of the background
gas with multiple ionization stages. 3. The inclusion of diagnostics to determine the
spectrum of electrons accelerated from the background plasma up to energies of the
order of 1 MeV, 4. The ability to calculate the orbits of test particles injected into the
wake (this has been carried out in collaboration with researchers at UCLA). Calculations
that have been performed in support of experiments at Maryland and elsewhere include:
1. Calculations of pulse propagation in gas jets and comparison with experimental FROG
data showing pulse shortening and retardation 2. Calculation of the generation of
filamentary electron density structures in gas jets and comparison with experimental
data. 3. Particle simulations showing the onset of energetic electron production near the
critical pressure for self focusing. 4. Calculations of laser wake coherence. 5. Test
particle calculations. Specific accomplishments are:
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Laser propagation in ionizing gases. An important issue for the effort at
Maryland is ability to inject a short laser pulse into the trough of a preformed plasma
channel. In the original scheme for plasma waveguides, the laser pulse must
propagate a distance through neutral gas in advance of the channel entrance. To
study this phase of the laser propagation the code WAKE (P. Mora and T. M.
Antonsen Jr., Phys Plasma 4, 217 (1997)) has been modified to describe the
ionization of a variety of different gases. The results of the code have been
compared with experiments performed at Maryland both for gas backfill and jets
[Opt. Lett. 22, 1787 (1997)]. An example of the predicted pulse deformations
appears below in Fig. 1. The results of the code have compared with experimental
FROG data, which can be used to determine the amplitude and phase of the pulse
after it emerges from the plasma [Opt. Comm. 157, 139 (1998)]. Refraction of the
front of the pulse produces an apparent shortening and retardation of the light
propagating on axis. The predicted and measured shortening and retardation were
found to be in good agreement.
Ionization Scattering Instabilities. Ionization induced refraction also leads to
interesting phenomena such as ionization scattering instabilities [Ionization induced
Scattering of Short Intense laser Pulses, T. M. Antonsen Jr. and Z. Bian, Phys Rev.
Lett 82, 3617 (1999)]. The instability is predicted to scatter the radiation and
create filamentary structures in the electron density profile left after the laser pulse
passes through the gas as illustrated in Fig. 2. More recently we have observed in
our experiments density striations and anomalous scattering consistent with the
presence of the ionization scattering instability [Observation of ionization instability of
intense laser pulses, Y. Li, S. P. Nikitin, Ilya Alexeev, H. M. Milchberg, and T. M.
Antonsen, Proceedings of the SPIE, 3776, 249 (1999), and submitted to Phys Rev.
Lett. (2000).] Calculations of the electron density profile showing striations have
been compared with side imaged femtosecond shadowgrams from the experiment.
In addition the radiation scattered at an angle from the laser axis shows striations in
intensity and upshifting which is also seen in the simulations. Figure 3 shows the
results of experiment and simulation of a 25 mJ, 100 fsec FWHM pulse with a
Gaussian radial profile of intensity focused in an argon gas jet. The jet has a
Gaussian shape with a HWHM of 0.5 mm and a peak atomic density of 2.2x1019 cm3. Plotted in the figure on the right are false color images of the electron density left
after the pulse has propagated through the jet and the wavelength spectrum of the
radiation passing through a radius r=147 µm. The ionization scattering instability
produces the many fine striations, or feathers, that appear in the electron density.
The plot on the right indicates the character of the scattered radiation. The plot
shows scattered light comes out in filaments that are blue shifted. On the left of Fig.
3 are two gray scale images obtained from the experiment. These are the side
imaged shadowgrams showing similar feather structures, and a spatially resolved
image of the scattered spectrum at a 40° angle from the laser axis. The experiment
shows that the creation of the feathers is accompanied by a blue shift in the
spectrum as in the simulation
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Generation of energetic particles. Particle simulations using the code wake have
been used to investigate the mechanisms for the production of energetic electrons.
Two distinct high energy tails can be observed in the simulations. The first, at
moderate energies (E < 1 MeV) correlates well with the conditions to observe
relativistic self-focusing. A plot of the number of accelerated electrons versus
pressure for several pulse energies appears in Fig. 4. Arrows indicate the critical
pressure for self-focusing for each pulse energy. The acceleration mechanism is a
combination of direct acceleration by the ponderomotive force and acceleration by
wave breaking of the plasma wave wake. The second tail with higher energy (E >
1MeV) appears when wave breaking occurs. This may occur in the self modulated
regime where a long pulse modulates and drives up a plasma wave, or in the short
pulse regime where a sufficiently intense pulse drives a large amplitude plasma
wave.
Plasma wake coherence. An issue is the coherence of the plasma wave wake.
During the year the code WAKE, developed in collaboration with P. Mora of the Ecole
Polytechnique in Palaiseau France, has been used to investigate the damping rate of
the plasma waves following a short laser pulse. The results were then compared
with measurements from experiments at Ecole Polytechnique. These are displayed in
Fig. 5. Damping times for wakes created in preformed plasmas are significantly
longer than those created in plasma formed in neutral gas jets due to ionization by
the incident laser pulse.
Acceleration of test particles. In collaboration with the group at UCLA, the code
WAKE has been modified to study the dynamics of test particles at ultra high energy.
This code is currently being used at UCLA to study the design of a 1GeV laser wake
field stage.
Publications:
1.
2.
3.
4.
5.
S. P. Nikitin, T. M. Antonsen, T. R. Clark, Y. Li, and H. M. Milchberg, “Guiding of
intense femtosecond pulses in preformed channels,” Optics Letters 22, 1787
(1997).
J. R. Marquès, F. Dorchies, F. Amiranoff, P. Audebert, J. C. Gauthier, J. P. Geindre,
A. Antonelli, T. M. Antonsen Jr., P. Chessa, and P. Mora, “Laser wakefield:
Experimental study of nonlinear radial electron oscillations,” Phys Plasmas 5, 1162
(1998).
T. M. Antonsen and Z. Bian, “Ionization Induced Scattering of Short Intense Laser
Pulses,” Phys Rev Lett 82, 3617 (1999).
P. Chessa, P. Mora and T. M. Antonsen Jr., “Numerical Simulation of short laser
pulse relativistic self-focusing in underdense plasma,” Phys Plasmas 5, 3451
(1998).
S. P. Nikitn, Y. Li, T. M. Antonsen and H. M. Milchberg, “Ionization induced pulse
shortening and retardation of high intensity femto second laser pulses,” Opt.
Comm., 139 (1998).
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Y. Li, S. P. Nikitin, I. Alexeev, H. M. Milchberg, T. M. Antonsen, and Zhigang Bian,
“Observation of ionization instability of intense laser pulses,” submitted to PRL
(2000).
L.O. Silva, W.B. Mori, R. Bingham, J.M. Dawson, T.M. Antonsen, and P. Mora,
“Photon Kinetics for Laser-Plasma Interaction,” IEEE Trans. Plasma Sci. to be
published (2000).
D.F. Gordon, W.B. Mori, and T.M. Antonsen Jr., “A Ponderomotive Guiding Center
Particle-In-Cell Code for Efficient Modeling of Laser-Plasma Interactions,” IEEE
Trans. Plasma Sci. to be published (2000).
P. Sprangle, B. Hafizi, J. Penano, R. F. Hubbard, A. Ting, A. Zigler, and T.
Antonsen, “Stable Laser Pulse Propagation in Plasma Channels for GeV Electron
Acceleration,” submitted to Phys Rev. E. (2000).
T. R. Clark and H.M. Milchberg, “Frequency-selective tunnel coupling to the plasma
fiber,” Phys. Rev. Lett. 81, 357 (1998).
T.R. Clark and H.M. Milchberg, “Time-and space-resolved density evolution of the
plasma waveguide,” Phys. Rev. Lett. 78, 2373 (1997).
T.R. Clark and H.M. Milchberg, “Laser-driven implosion of a cylindrical plasma,”
Phys. Rev. E 57, 3417 (1998).
V. Kabelka, M. Masalov, S.P. Nikitin, and H.M. Milchberg, “Tracing the phase
distortion of a single ultrashort light pulse from angularly resolved secondharmonic generation,” Optics Communications 156, 43 (1998).
T.R. Clark and H.M. Milchberg, “Optical mode structure of the plasma waveguide,”
Phys. Rev. E 61, 1954 (2000).
J. Fan, T.R. Clark, and H.M. Milchberg, “Generation of a plasma waveguide in an
elongated, high repetition rate gas jet,” Appl. Phys. Lett. 73, 3064 (1998)
S.P. Nikitin, I. Alexeev, J. Fan, and H.M. Milchberg, “High Efficiency coupling and
guiding of intense femtosecond laser pulses in preformed plasma channels in an
elongated gas jet,” Phys. Rev. E 59, R3839 (1999).
J. Fan, E. Parra, and H.M. Milchberg, “Resonant self-trapping and absorption of
intense Bessel Beams,” Phys. Rev. Lett. 84, 3085 (2000).
T.R. Clark and H.M. Milchberg, “Time-evolution and guiding regimes of the laserproduced plasma waveguide,” Phys. Plasmas 7, 2192 (2000).
J. Fan, E. Parra, I. Alexeev, K.Y.Kim, H.M. Milchberg, L. Margolin, and L.
Pyatnitskii, “Tubular plasma generation with a high power hollow Bessel beam,”
submitted to Phys. Rev. E, Rapid Communications (2000).
Current staff:
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Milchberg, H.M.
Antonsen, T.M.
Alexeev, I
Kim, K. Y.
Fan, J.
Bien, Z.
Cooley, J.
Jianzhou, Wu.
Co-PI
Co-PI
Grad Student
Grad Student
Grad Student
Grad Student
Grad Student
Grad Student
Professor Howard Milchberg (PI)
University of Maryland
Inst. Physical Science and Technology Bldg 2123
College Park, Maryland 20742-2431
PHONE: 301/405-4816
Accelerator Research Studies (Tasks A and B)
M. Reiser – University of Maryland, Institute for Plasma Research
Summary (TASK A):
The Accelerator Research Studies Program at the University of Maryland consists of two
tasks: 1. TASK A, “Study of the Physics of Space-Charge Dominated Beams for
Advanced Accelerator Aplications” (Co-PI’s P. O’Shea and M. Reiser), 2. TASK B:
“Studies of High-Power Gyroklystrons with Application to Linear Colliders” (Co-PI’s V.
Granatstein, W. Lawson, P. O’Shea, and M. Reiser). In this report the two tasks will be
presented separately.
During the past decade, our research in TASK A has focused on the physics of intense,
space-charge dominated beams. This work is of vital importance for the development of
more intense high quality beams for such applications as spallation neutron sources,
high-energy physics colliders, and light sources. In our program we have studied
phenomena relating to emittance growth, longitudinal instability, and equipartitioning in
beams of increasing intensity and complexity. We have been a leader in the application
of thermodynamic principles to the study of beams. A hallmark of our program has
been the use of low-energy electron beams to model the space-charge physics and the
close connection between theory, simulation and experiment.
In the early phases of this work we have focused our efforts on linear beam systems
with solenoidal focusing. In the past few years we have begun the study of intense
beams in a dispersive lattice with strong focusing. This work will culminate with the
construction of the University of Maryland Electron Ring (UMER) (see figure). Generally,
circular accelerators and rings have been limited to lower intensities than linear
accelerators to avoid destructive resonances in a circular lattice. At higher intensities,
collective effects will dominate over single particle effects. Because of the lack of
experimental data, almost all of our understanding in this region is based on theory,
simulation and conjecture. UMER currently under construction, is a low-cost flexible
electron model of high-intensity recirculators and rings.
Major accomplishments of our research during the past two years can be summarized
as follows:
• In the longitudinal resistive-wall instability experiment, we found an unexpected
change in the behavior of the space-charge waves when the initial amplitude of the
perturbation is increased: the fast wave is transformed into a slow wave. Further
studies are necessary to obtain an understanding of this phenomenon, for which so
far no theoretical explanation exists.
• An important factor in the longitudinal beam physics is the evolution of energy
spread. Preliminary measurements of the energy spread with an improved highresolution energy analyzer were in relatively good agreement with the expected
effects of Coulomb collisions.
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In experiments on the UMER prototype injector, we have observed unanticipated
radial density oscillations that propagate inwards from the edge of the beam (see
figure). This phenomenon appears to be fairly universal, and its further
understanding is desirable for many high-intensity accelerators.
During the past year the design of UMER has been completed, the major
components have been acquired, testing of the electron gun and measurements of
the electron beam has started.
Publications (TASK A):
1. J. G. Wang and M. Reiser, "Longitudinal space-charge waves and instabilities in
intense beams", Phys. Plasmas, 5(5), 2064-2070 (1998).
2. M. Venturini and M. Reiser, "Self-consistent beam distributions with space charge
and dispersion in a circular ring lattice", Phys. Rev. E, 57, 4725-4732 (1998).
3. J. G. Wang, S. Bernal, P. Chin, R. A. Kishek, Y. Li, M. Reiser, M. Venturini, Y. Zou, T.
Godlove, I. Haber, and R. C. York, "Studies of the physics of space-charge
dominated beams for heavy ion inertial fusion", Nucl. Insert. & Meth. in Phys. Res.
A. 415, 422-427 (1998).
4. R. A. Kishek, S. Bernal, M. Reiser, M. Venturini, J. G. Wang, I. Haber, and T.
Godlove, "Beam dynamics simulations of the University of Maryland E-Ring project",
Nucl. Instr. & Meth. in Phys. Res. A. 415, 417-421 (1998).
5. M. Venturini and M. Reiser, "RMS envelope equations in the presence of space
charge and dispersion," Phys. Rev. Lett. 81, 96 (1998).
6. S. Bernal, P. Chin, R. Kishek, Y. Li, M. Reiser, H. G. Wang, T. Godlove, and I. Haber,
"Transport of a space-charge dominated electron beam in a short-quadrupole
channel," Phys. Rev. ST Accel. Beams 1, 044202 (1998).
7. S. Bernal, R. A. Kishek, M. Reiser, I. Haber, "Observations and Simulations of
Transverse Density Waves in a Collimated Space-Charge Dominated Electron Beam,
Phys. Rev. Lett. 81, 4002 (1999).
8. H. Suk, J.G. Wang, M. Reiser, and Y. Zou, “Experiments on Space-charge Waves in
Electron Beams Propagating through a Resistive-Wall Channel”, Journ. Appl. Phys.
86, 1699 (1999).
9. Y. Zou, J.G. Wang, H. Suk, and M. Reiser, “Nonlinear Behavior of Localized SpaceCharge Waves in Space-Charge Dominated Beams”, Phys. Rev. Lett. 84, 5138
(2000).
10. R.A. Kishek, P.G. O’Shea, and M. Reiser, “Energy Transfer in Non-Equilibrium SpaceSpace Dominated Beams”, Phys. Rev. Lett. 85(21), 4514-4517, 2000.
Current Staff (TASK A)
Reiser, M.
O’Shea, P. G.
Kishek, R.
PI, Professor Emeritus and Senior Research Scientist
PI, Associate Professor, Electrical and Computer Engineering
Assistant Research Scientist
Bernal, S.
Valfells, A.
Yun, V.
Schoonover, J.
Cui, Y.
Li, H.
Harris, J.
Virgo, M.
Bryan Quinn
Navid Rahim
Matt Holland
Robert Yun
Matt Glanze
Chris Graboski
Task A figures
Research Associate
Research Associate
Mechanical Engineer
Secretary
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Undergraduate
Undergraduate
Undergraduate
Undergraduate
Undergraduate
Undergraduate
Summary (TASK B):
The purpose of the TASK B program is to evaluate gyroklystron amplifiers as RF
drivers for high-energy linear accelerators with RF frequency in the range 17.1 to
91.4 GHz. This frequency range is higher than is presently used in HEP accelerators.
The higher RF frequency is expected to enable larger accelerating gradients so that
accelerator length can be kept within tolerable limits as final energy is increased to
the TeV range.
An early accomplishment of the program was the demonstration of a frequency
doubling gyroklystron with output peak power of 30 MW at a frequency of 20 GHz.
The present thrust of the program is to significantly increase the output power. To
this end, a 17.14 GHz, frequency doubling gyroklystron is being developed which is
expected to have output power approaching 100 MW in microsecond pulses; such
performance would significantly surpass the performance of conventional klystrons
in terms of the output power density parameter (peak power divided by wavelength
squared). One innovation required to achieve the increased power capability is the
use of a co-axial circuit in the gyroklystron.
During the past few years, a preliminary experiment on a 3-cavity coaxial
gyroklystron without the frequency doubling feature performed well producing
output pulses of 80 MW at 8.57 GHz. More recently, initial operation of a 3-cavity,
coaxial, gyroklystron has been achieved with the frequency-doubling feature in
operation so that output was at 17.14 GHz. Work to optimize the performance of
this amplifier is in progress.
A follow-on experiment will involve development of a 4-cavity amplifier. A 4-cavity,
harmonic doubling gyroklystron circuit has been designed and fabricated. Predicted
performance of an amplifier employing this circuit includes 60 dB gain, 37%
efficiency and output power of 90 MW. The higher gain that can be achieved with 4
cavities allows one to obtain the gyroklystron input signal from a TWT amplifier
rather than a magnetron, and thereby achieve phase control of the gyroklystron
output signal.
This 4-cavity, coaxial gyroklystron will be used to drive a 17.14 GHz high gradient
linac section being developed by the Haimson Corporation. Accelerating gradients in
the linac section may approach 200 MV/m. Finally, gyroklystrons have also been
designed at 34.3 and 91.4 GHz with predicted output powers of 55 MW and 20 MW
respectively.
Publications (TASK B):
1. G. P. Saraph, V. L. Granatstein, and W. Lawson, “Design of a Single-Stage
Depressed Collector for High Power, Pulsed Gyroklystron Amplifiers,” IEEE Trans.
Electron Dev. 45, pp. 986-990 (1998).
1. M. Castle, J. Anderson, W. Lawson, and G. P. Saraph, "An Overmoded Coaxial
Buncher Cavity for a 100 MW Gyroklystron", IEEE Microwave and Guided Wave
Letters, 8, pp. 302-304 (1998).
2. W. Lawson, J. Cheng, M. Castle, B. Hogan, V. L. Granatstein, M. Reiser, and G.
P. Saraph, "High Power Operation of a Three-Cavity X-Band Coaxial
Gyroklystron," Phys. Rev. Lett., 81, pp. 3030-3033 (1998).
3. M. R. Arjona and W. Lawson, “Design of a 7 MW, 95 GHz, Three-Cavity
Gyroklystron,” IEEE Trans. Plasma Sci., 27, pp. 438-444 (1999).
4. X. Xu, C. Liu, J. Anderson, J. Cheng, W. Lawson, B. P. Hogan, and V. L.
Granatstein, “Development of an X-Band Advanced-Concept Input System for
High-Power Gyroklystron,” IEEE Trans. Plasma Sci., 27, pp. 520-530 (1999).
5. J. Cheng, X. Xu, W. Lawson, J. P. Calame, M. Castle, B. P. Hogan, and V. L.
Granatstein, G. S. Nusinovich, and M. Reiser, “Experimental Studies of a HighPower, X-Band, Coaxial Gyroklystron,” IEEE Trans. Plasma Sci., 27, pp. 11751187 (1999).
6. W. Lawson, M. R. Arjona, B. Hogan, and R. L. Ives, “The Design of Serpentine
Mode Converters for High Power Microwave Applications,” IEEE Trans.
Microwave Theory Tech., 48, pp. 809-814, (2000).
7. W. Lawson and M. R. Arjona, “The Application of Scattering Matrices to ReEntrant Cavities,” To be published October 2000 in Int. J. Electronics.
8. M. R. Arjona and W. Lawson, “Design of a 34 GHz Second-Harmonic Coaxial
Gyroklystron Experiment for Accelerator Applications,” To be published June
2000 in IEEE Trans. Plasma Sci.
9. Yovchev, W. Lawson, G. S. Nusinovich, V. L. Granatstein, and M. Castle, “Present
Status of a 17.1 GHz Four-Cavity Frequency-Doubling Coaxial Gyroklystron,” To
be published June 2000 in IEEE Trans. Plasma Sci.
Current Staff (TASK B):
Reiser, M.
Granatstein, V.L.
Lawson, W.
O’Shea, P. G.
Nusinovich, G.
Spassovsky, I.
Hogan, B.
Schoonover, J.
Castle, M.
Gouviea, S.
PI, Professor Emeritus and Senior Research Scientist
PI, Professor, Electrical and Computer Engineering
PI, Professor, Electrical and Computer Engineering
PI, Assoc. Prof., Electrical and Computer Engineering
Senior Research Scientist
Visiting Scientist
Engineer
Secretary
Graduate Student
Graduate Student
Kim, V-G
Cassedy Newgen
Nick Dzurec
Nassir Benammar
Task B figures
Graduate Student
An All-Optical Laser Wakefield Electron Injector
D. Umstadter -University of Michigan
Summary:
Using compact (table-top-size) solid-state lasers-which produce ultrashort pulses,
multi-terawatt peak powers, and intensities exceeding 1019 W/cm2-we are conducting
an experimental study of a novel accelerator concept, an all-optical laser-wakefield
electron injector. This plasma-based electron gun uses ultrahigh-gradient
laser-wakefield plasma waves for acceleration, and employs the plasma itself as a
laser-triggered photo-cathode. It will eventually be used for injection of electrons into
existing RF accelerators or further laser accelerator stages.
Our theoretical and numerical studies [1, 2] indicate that this method can produce
electron bunches with parameters comparable to those of RF-linacs but with
orders-of-magnitude shorter electron pulse durations (femtosecond uncompressed and
subfemtosecond compressed). As an injector stage for linear electron colliders for
nuclear and high-energy physics, this pulse length reduction may have several
interesting consequences. In the case of an electron-electron linear collider, it would
have a higher limit on attainable luminosity by permitting a shorter β (in effect, the
Rayleigh parameter of the magnetic optics) at the final focus/intersection point, and it
would also reduce beam-beam effects by reducing the time during which the beams
overlap. There would also be a reduction in beam-beam Bremsstrahlung
("beamstrahlung") due to quantum mechanical effects. By synchronizing and matching
the electron pulse duration to that of the acceleration bucket, our laser-injection
concept will reduce the energy spread of plasma guns. Additionally, the ultrahigh-field
gradient in the primary acceleration stage has been shown to result in lower beam
emittance, which is another way in which our concept may increase the luminosity of
colliders and the gain of free-electron lasers. Due to the potentially large reduction of
the required length of the wigglers, plasma guns are now being considered for the
injector stage of the proposed Linac Coherent Light Source (LCLS).
We are currently testing several current laser injection concepts and fully characterizing
the resulting electron beam in terms of energy, charge, emittance, and pulse duration.
Before laser injection can be achieved, several basic issues involving the interaction of
intense, short-pulse laser pulses with underdense plasmas need to be explored and the
accelerating structure of a resonant wakefield plasma wave needs to be fully
characterized. In the last year we have made two important breakthroughs: (1) We can
now explain with a simple theory the experimentally measured emittance properties of
electron beams accelerated by a plasma gun, the transverse component of which also
happen to be the lowest ever recorded. (2) We have conducted the first study of
laser-based electron acceleration, driven (in the resonant regime) by ultrashort-duration
(30 fs) laser pulses at high repetition rate (10 Hz). The former parameter is an order of
magnitude shorter, and the latter is several orders of magnitude higher, than in
previous studies.
•
In order to implement the laser injection of electrons with a wakefield accelerator,
the first step is to generate a large amplitude longitudinal plasma wave. As
described in [3], the electron beam generated in a self-modulated laser-wakefield
accelerator was characterized in detail. A transverse normalized emittance of 0.06
π-mm-mrad, the lowest ever for an electron injector, was measured for 2 MeV
electrons. The electron beam was observed to have a multi-component beam profile
and energy distribution. The latter also undergoes discrete transitions as the laser
power or plasma density is varied. In addition, dark spots that form regular modes
were observed in the electron beam profile. These features are explained by
analysis and test particle simulations of electron dynamics during acceleration in a
three-dimensional plasma wakefield.
•
As described in [4], the interaction of ultrashort, high-intensity laser (810 nm, 29 fs,
intensity up to 3 × 1018 W/cm2) with underdense plasma of ionizing gas was studied.
Relativistic self-focusing is observed from the measurement, and the microscopic
imaging of the light transmitted through the plasma. With the onset of relativistic
self-focusing, relativistic filamentation grows and the light is scattered out of the
vacuum propagation angle. Mega-electron-volt electrons are generated in the
forward direction, and the divergence angle of the main electron beam is as small as
1°, which we believe originates from the relativistic filamentation.
Publications:
1. D. Umstadter, J. K. Kim, and E. Dodd, "Laser Injection of Ultrashort Electron Pulses
into Wakefield Plasma Waves," Phys. Rev. Lett. 76, 2073 (1996).
2. E. Dodd, J. K. Kim and D. Umstadter, "Electron Injection by Dephasing Electrons with
Laser Fields," Advanced Accelerator Concepts: Eighth Workshop, edited by W.
Lawson, C. Bellamy, and D. Brosius, AIP Conference Proceedings 472 (AIP Press,
New York, 1999), p. 886.
3. S.-Y. Chen, M. Krishnan, A. Maksimchuk, and D. Umstadter, "Excitation and Damping
of a Self-Modulated Laser Wakefield," Physics of Plasmas, 7, 403 (2000).
4. X. Wang, M. Krishnan, N. Saleh, H. Wang and D. Umstadter, "Electron Acceleration
and the Propagation of Ultrashort High-Intensity Laser Pulses in Plasmas," Phys.
Rev. Lett. 84, 5324 (2000),
5. D. Umstadter, S.-Y. Chen, G. Ma, A. Maksimchuk, G. Mourou, M. Nantel, S. Pikuz, G.
Sarkisov and R. Wagner, "Dense and Relativistic Plasmas Produced by Compact
High-Intensity Lasers," Astrophysical Journal Supplement Series 127, 513-518,
(2000).
6. S.-Y. Chen, M. Krishnan, A. Maksimchuk, R. Wagner and D. Umstadter, "Detailed
Dynamics of Electron Beams Self-Trapped and Accelerated in a Self-Modulated Laser
Wakefield," Physics of Plasmas, 6, 4739 (1999).
7. K. Assagaman, W. W. Buck, S.-Y. Chen, R. Ent, R. N. Green, P. Gueye, C. Keppel, D.
Umstadter, G. Mourou, R. Wagner, "Electron beam characteristics of a laser-driven
plasma wakefield accelerator," Nucl. Instr. Meas. A 438, 265 (1999).
8. J. K. Kim and D. Umstadter, "Cold Relativistic Wavebreaking Threshold of
Two-Dimensional Plasma Waves," Advanced Accelerator Concepts: Eighth
Workshop, edited by W. Lawson, C. Bellamy, and D. Brosius, AIP Conference
Proceedings 472 (AIP Press, New York, 1999), p. 404.
9. H. Wang, S. Backus, Z. Chang. R. Wagner, X. Wang, T. Lei, M. Murnane and H.
Kapteyn, "Generation of 10-W Average-power, 40-TW Peak-power, 24-fs pulses
from a Ti:Sapphire Amplifier System," J. Opt. Soc. Am. B 16, 1790 (1999).
10. G. S. Sarkisov, V. Yu. Bychenkov, V. N. Novikov, V. T. Tikhonchuk, A. Makismchuk,
S. -Y. Chen, R. Wagner, G. Mourou and D. Umstadter, "Self-focusing, channel
formation and high-energy ion generation in the interaction of an intense short laser
pulse with a He jet," Phys. Rev.E 59 7042 (1999).
Current Staff:
•
•
Donald Umstadter
Ned Saleh
PI
Graduate Student
NOTE: several undergraduate students are also supported by the DOE Washington
Administered Program in Technology R&D. Numerous papers [1] [2] [4] [5][6] [7] [8]
resulting from work supported by the DOE contract were published in the last three
years. The program also indirectly benefits from the partial support of the National
Science Foundation on electron spectrometer construction (in collaboration with
scientists and students at Hampton University and TJNAF) [7], high-intensity laser
development [9] and supporting experiments (at the Center for Ultrafast Optical
Science, University of Michigan, Ann Arbor) [101].
Prof. Donald Umstadter
University of Michigan
1006 IST
Ann Arbor, Michigan
PHONE: 734 647-6214
Investigations of Beam Dynamics Issues
at Current and Future Hadron Colliders
University Program at the University of New Mexico
J.A. Ellison, University of New Mexico
T. Sen, Fermilab
Summary:
This project was funded by DOE based on a proposal by Ellison and Sen for joint work
at the University of New Mexico while Sen was working at DESY. Before the project was
actually funded Sen accepted a position at Fermilab. However, he remains deeply
interested in the topics of our joint proposal, is a no-fee co-investigator on the project
and a ready source of valuable accelerator physics expertise.
There are many significant problems in beam dynamics that are at the forefront of what
is understood in dynamical systems, stochastic processes and scientific and high
performance computing. This makes it an ideal area for interaction between universities
and accelerator labs. The Advanced Technology R&D Program at DOE makes this
possible. We have an ideal situation at UNM because our applied mathematics group is
a good source of expertise in the underlying areas of mathematics, UNM has two
national high performance computing centers and we have close collaborations with
researchers in accelerator laboratories as well as mathematical scientists at other
universities.
The project has several foci: Beam-Beam Interaction, Nonlinear Longitudinal Collective
Effects due to Wake Fields, Space Charge, Vlasov Equation, and Spin Dynamics.
•
Vlasov Equation. We have initiated a major study of the Vlasov equation in beam
dynamics. This involves existence of equilibrium solutions, linearized behavior about
equilibria, development of a weakly nonlinear theory, and a study of fully nonlinear
effects such as solitary waves and turbulence. Finally, we have developed a
numerical algorithm for its integration that we anticipate will have wide application.
•
Beam-Beam Interaction. A paper on the weak-strong beam-beam with noise due
•
Longitudial Nonlinear Collective Effects Due to Wakefields. We made a major
to tune fluctuations, beam offsets and beam size fluctuations is nearly complete.
Work is in progress on the strong-strong beam-beam on two fronts: Macro particle
tracking to compute moments and analysis based on a time-domain numerical
integration of the Vlasov equation.
advance on understanding the saw-tooth instability in the SLAC damping rings. We
are making good progress on the proton case for Fermilab beams, as pioneered by
Colestock and Spentzouris, following the Vlasov equation approach.
•
Space Charge. We are studying space charge based on the Vlasov equation
approach, following the LEDA experiment at Los Alamos, and beginning involvement
with the proton driver now under study at Femilab.
•
Spin Dynamics. We have finished a paper on the spin tune, are working on the
•
problem of the existence of a spin equilibrium state, and analyzing the adiabatic
invariance of this equilibrium as the beam energy changes slowly.
Most Significant Accomplishments. The development of an algorithm and a code
for solving the Vlasov equation in general and its application to the saw-tooth
instability and the beam-beam interaction. The former has been compared with
experiment and there is good agreement. The investigation of equilibrium solutions
of the Vlasov equation including a proof of existence in the beam-beam, electron
case. The clarification of spin tune and the proof of the adiabatic invariance of the
invariant spin field.
Current Staff:
•
•
•
•
J. Ellison – PI
T. Sen – Co-PI (Fermilab)
M. Vogt – Post doc
I. Vlaicu – Graduate Research Assistant
SUPPLEMENTARY INFORMATION
OVERVIEW & HIGHLIGHTS
Excellent progress has been made in the 17 months since the grant was awarded in
April 1999. We are confident that continued support will bring major contributions to
the beam dynamics community. Even though the Principal Investigator is only
supported by the grant during the summer his total research effort is devoted to the
project. In addition, the Co-Investigator is giving significant support to the project
(with no compensation from the grant).
The spin work is nearing completion, and there will be three papers; one related to a
new characterization of spin tune, another concerning the existence of an invariant
spin field and the third a theory of adiabatic invariance which is important for
accelerating polarized protrons. We have made significant progress on the Vlasov
equation for beam dynamics and on the strong-strong beam-beam; both analytically
and numerically. In the near future, our numerical work will be coded in parallel and
run in one of UNM's high-performance computing environments.
Pat Colestock has moved to Los Alamos, which gives a boost to the nonlinear
longitudinal collective work for hadron colliders that he initiated at Fermilab. We
continue to develop a good base of collaborators and advisors with expertise covering
the gamut of our work - our main collaborators are listed below. In particular, Bob
Warnock is making significant contributions to our program. A graduate research
assistant has been studying under the grant. A Postdoc has been has been hired as of
July 1, 2000 and in just two months has made excellent progress on the Beam-Beam.
The DOE award has given me helpful leverage. Four colleagues in the mathematics
department and I were awarded a cost-sharing “SCREMS” grant from NSF for a small
parallel platform (9 node Alpha cluster) to be used by us for code development. This is
helpful because code development is difficult in major high-performance computing
environments. We believe the DOE grant was an important selling point and the
equipment will boost the parallel computing part of our work. In addition, I argued to
my departmental chair and the dean of A&S for a reduced teaching load based on the
award. They agreed and I will be released from one course each year. Of course,
teaching is still very important. It gives me contact with students who can be potential
contributors to beam dynamics and keeps me honed on applied mathematical
techniques of relevance to the grant. Last fall I taught a graduate course on stochastic
differential equations. This took a great deal of time, but there were several benefits
related to the grant. It led to an important piece of the beam-beam work with
Warnock, exposure to this important area for the graduate research assistant and a
new proof of a significant result for beam dynamics with noise. I have been teaching
our Partial Differential Equation courses and am currently teaching the advanced one.
Not only will this be beneficial for our work on the Vlasov equation, but I am able to
present interesting examples from the beam dynamics work.
COLLABORATORS
Collaborators are crucial to the success of our work. The following are people with
whom we are currently working or with whom we have detailed research plans in place
related to the topics of the grant. Discussions are going on with several other
researchers in the accelerator community. Alejandro Aceves (UNM-expert in nonlinear
PDEs and solitons), Desmond Barber (DESY-expert on spin dynamics both experiment
and theory), Court Bohn (Fermilab-expert on space charge), Pat Colestock (LANL-expert
on accelerator and plasma physics), Scott Dumas (U. of Cincinnati-expert on dynamical
systems and perturbation theory), Françoise Glose (Ecole Normale Supérieure, expert
on Kinetic Theory and abstract PDE's), Klaus Heineman (DESY- expert on the
mathematics of spin), Georg Hoffstätter (DESY-expert in beam dynamics and
related spin issues), Linda Spentzouris (Fermilab – experimental expert on nonlinear
collective effects in Fermilab beams), Robert Warnock (SLAC-expert on beam dynamics
and related mathematics and computation), and Maria Paz Zorzano (CERN - expert on
noise in beam dynamics).
GRADUATE RESEARCH ASSISTANT & POSTDOC
We have a graduate research assistant (Irina Vlaicu) and a Postdoc (Mathias Vogt) on
board. Vlaicu has finished her course work for the master's degree and is working on
the qualifying exams for the Ph.D. In addition to basic studies in beam dynamics, she is
working with Sen and me on the weak-strong beam-beam problem with noise. After
passing the qualifying exams, she will start a beam dynamics thesis. She joined Aceves
and me for a week at Fermilab. She was excited to be there, she met Sen and others
and it was a good experience for her. Vogt was hired as of July 2000. He is spending
his first three months at Fermilab working with Sen and me, and then will move to New
Mexico. He is making excellent progress on the strong-strong beam-beam.
VLASOV EQUATION(VE)
Each of the three main areas of our work, the strong-strong beam-beam, nonlinear
longitudinal collective effects and space charge, can be formulated in terms of the
Vlasov equation. This is a nonlinear-integro-partial-differential equation which evolves
the phase space density of the particle beam. We have begun a major program to
study this equation both with analytic and numeric methods.
While the Vlasov equation would seem to provide a solid basis for a wide class of
problems in accelerator physics, the analysis of its solutions is still in a primitive state.
For many years the main work was in linear stability studies. We are refining these
linearization studies, including the important question of the existence of (nonlinear)
equilibria, developing a weakly nonlinear theory, as in the three-wave coupling, and
looking at fully nonlinear effects, such as solitary wave solutions and the possibility of
weak turbulence (Colestock and Spentzouris saw hints of the latter at Fermilab).
Some exciting results have come out of the collaboration with Bob Warnock. Together
we are developing numerical procedures for integrating the VE. In fact the procedures
apply to the Liouville, Vlasov and Vlasov-Fokker-Planck equations. The technique, based
on discretization of the Perron-Frobenius operator, is simple in concept, easy to
implement, and numerically stable in examples studied to date. Two problems have
been studied in some detail: (i) longitudinal dynamics in electron storage rings with
realistic wake field, and (ii) one-dimensional transverse motion in electron storage rings
with coherent beam-beam collisions. In example (i) we report a simulation of the SLAC
damping rings, and find good agreement with several aspects of observations, including
the presence of the bursting (sawtooth) mode, with period comparable to the damping
time. The attached figure shows the time evolution of the dimensionless bunch length.
A fairly clear periodic behavior sets in at about 2.5 damping times(500 synchrotron
periods). This is Figure 1 from Publication 1 below. In example (ii) we find an
equilibrium state, the existence of which has long been in question. Inspired by this
numerical result, we formulate an integral equation for the equilbrium, and prove that it
has a unique solution for sufficiently small current. Encouraged by results in one degree
of freedom, we look forward to applications in higher dimensions and the replacement
of electrons by hadrons, and especially to an important class of topics that might be
called generalized equilibrium problems. This class includes the issue of equilibrium and
quasi-equilibrium (time-periodic) distributions in rings, and the question of “matched
distributions” with space charge and/or radiation in single-pass systems; for instance,
the halo problem in linacs and rings.
Aspects of this work were presented at the ICFA Workshop on The Physics of
Highbrightness Beams at UCLA in November 1999 and the paper “A general method for
propagation of the phase space distribution, with application to the saw-tooth
instability” will appear in the proceedings. At the APS meeting in Long Beach in April
2000 we presented two papers, “Equilibrium state of stored electron beam with
coherent beam-beam interaction” and “Bunch lengthening and bursting mode in a
simulation of the SLAC damping rings,” in the mini-symposium Simulation of Beams
with Strong Collective Forces organized by Bill Herrmannsfeldt. The paper “Simulation
of bunch lengthening and saw-tooth mode in SLAC damping rings” was presented at
EPAC 2000 in Vienna. In addition, Warnock presented our results at the SLAC
Workshop on Broadband Impedance Measurements and Modeling in February 2000 and
in talks at Lawrence Berkeley in July and Fermilab and Argonne in August 2000.
STRONG-STRONG-BEAM-BEAM FOR HADRONS
The basic problem has been formulated and we have developed two algorithms for
numerical computation. The work with Warnock will be extended to hadrons and an
approach developed by Sen, which calculates moments by following macro-particles, is
being pursued. The codes will be written in parallel, the code development will be done
on the Math Department's new parallel platform mentioned above and the codes will be
run at UNM's high performance computing center. On the analytic side, Aceves, Sen
and I are developing a weakly nonlinear theory which we hope will show mode
coupling, for example between the so-called pi and sigma modes. In addition, Warnock
and I are studying possible equilibrium or quasi-equilibrium states using the techniques
we developed above. Experimentally these states appear to exist for reasonable times.
Theoretically, the situation seems more difficult than the electron case, because of the
lack of the combined effect of damping and diffusion due to radiation. Our progress will
be reported at the Second Workshop on Beam-Beam Effects in Large Hadron Colliders
organized by Sen and taking place at Fermilab in Spring 2001. The beam-beam will be
a major effort of our Postdoc Mathias Vogt.
WEAK-STRONG BEAM-BEAM
Sen and his collaborators at Fermilab and CERN have continued our work on this in: 1)
Effect of the beam-beam interactions and the dynamic aperture in the LHC, T. Sen
et.al. (FNAL-Conf-99-148), 2) Emittance growth for the LHC beams due to the beam-
beam interaction and ground motion, M.P. Zorzano and T. Sen (to be published as a
LHC report and FNAL report).
Sen, Vlaicu, Zorzano and I have continued to work on the 2 degree-of-freedom case
with tune, beam offset and beam size fluctuations. We derive diffusion coefficients
based on the linear actions and model the beam evolution by a diffusion equation
approximation. The method of averaging has been extended to help guide our
approximations in the derivation of the diffusion coefficient and a numerical code has
been developed to integrate the diffusion equation. A paper on this is nearly complete.
NONLINEAR LONGITUDINAL COLLECTIVE EFFECTS – HADRONS
This is work with Pat Colestock and Linda Spentzouris, some of which they discussed in
a special course The Plasma Physics in Beams at the January 2000 US Particle
Accelerator School in Tucson, and with Aceves. On the experimental side, Spentzouris
is proposing to do experiments on Fermilab beams. Her goal is to compare
experimental results with theoretical models for the high frequency, longitudinal
fluctuation spectra in beams, and determine the degree of nonlinearity present and the
scaling laws at work. The results would have implications regarding the evolution of
beam emittance, and in the dynamics involved with beam cooling. On the theoretical
side, we are applying the analysis outlined in the second paragraph of the VE Section.
We have solved the linearized problem which may be a new result. Aceves, Colestock
and I are developing a weakly nonlinear theory and we have also refined our soliton
calculation. On the numerical side an important advance will come with the
implementation of the Warnock/Ellison numerical method described above. The stage
is set for significant progress, as soon as time permits, and some of this work will make
a fine Ph.D. thesis.
SPACE CHARGE
The workshop on The Physics of High Brightness Beams at UCLA was useful. The
core-halo model was much discussed and much seemed to be based on a particular
model developed by Gluckstern. The basic open issue in this model has to do with the
separatrix crossing problem and there is work to be done here. A step in this direction
has been taken by Bazzani and independently by Haberman, building on the work of
Neistadt. I would like to study this work. Pat Colestock and colleagues are designing
an experiment at Los Alamos to test this model and I plan to be involved at some level
because I think it will have important implications for rings. We are also beginning
discussions related to the future proton driver under study at Fermilab for which space
charge is the major issue. The numerical work with Warnock can be applied to space
charge as well as the type of analysis mentioned in the second paragraph of the Vlasov
Equation Section. Space Charge is a good Ph.D. thesis area.
SPIN
The paper “A quasiperiodic treatment of spin-orbit motion in storage rings - a new
perspective on spin tune” is nearly ready for publication. In this paper we show how
spin motion on the periodic closed orbit of a storage ring can be analyzed in terms of
the Floquet theorem for equations of motion with periodic parameters. The spin tune on
the closed orbit emerges as an extra frequency of the system which is contained in the
Floquet exponent in analogy with the wave vector in the Bloch wave functions for
electrons in periodic atomic structures. We then proceed to show how to analyze spin
motion on quasi-periodic synchro-betatron orbits in terms of a generalization of the
Floquet theorem and we find that provided small divisors are controlled by applying
a Diophantine condition, a spin tune can again be defined and that it again emerges as
an extra frequency in a Floquet-like exponent. We thereby obtain a deeper insight into
the concept of “spin tune” and the conditions for its existence. It will appear as a DESY
red report and we will likely submit it to Physica D. It is joint work with Desmond
Barber and Klaus Heinemann both from DESY. The results will be presented at
the 14th International Spin Physics Symposium, SPIN2000, Oct. 16-21, 2000 in Osaka,
Japan hosted by the RCNP, Osaka University.
The paper “Applying ergodic theorems to stroboscopic averaging of Liouville densities
and spin fields” with Klaus Heinemann at DESY is nearly complete. Here a class of
orbital systems with volume preserving flows is defined which is periodic in the
azimuthal variable and the Liouville densities are considered. Performing stroboscopic
averaging and applying the Birkhoff Ergodic Theorem one gets Liouville densities which
are periodic in the azimuthal variable. More importantly, particles with both spin and
integrable orbital motion are considered. For the resulting class of spin-orbit motions
the polarization densities are considered and by performing stroboscopic averaging one
gets, via the Birkhoff Ergodic Theorem and the Von Neumann Ergodic Theorem,
polarization densities which are periodic in the azimuthal variable. This demonstrates
that the tracking algorithm, encoded in the program SPRINT and used in the simulation
of spin polarized storage rings, is mathematically well founded. Some simple examples
are considered and a tracking algorithm is derived which computes Liouville densities
which are periodic in the azimuthal variable.
Georg Hoffstätter of DESY has just written a major thesis on spin dynamics which
focuses on the problem of accelerating a polarized beam of protons to 920 GeV in the
HERA proton ring at DESY. This thesis is one of the requirements for the German
Habilitation degree. The problem of obtaining a polarized proton beam at these high
energies is a very difficult one because, unlike electrons, spin flip polarization is too
weak to be useful. However the high energy physics community is eager to have
polarized protons at the top energy of the HERA proton ring. Several methods have
been considered but the most promising is the acceleration of polarized protons after
creation in a polarized source. I have collaborated with Georg on a theoretical aspect
of this work; the adiabatic spin invariant on phase space trajectories. Here we apply
the method of averaging in a fairly abstract form to argue that this invariant
spin field is an adiabatic invariant as the beam energy is slowly varied, even though
many resonances are crossed during the acceleration process. This is not very satisfying
and we want to show the result directly. We are working on this with Dumas. The
work with Dumas and Golse (item (3) below) where we use a cut-off Diophantine
condition may be important here.
PUBLICATIONS
1. R.L. Warnock and J.A.Ellison, “A General Method for Propagation of the Phase Space
Distribution, with Application to the Saw-Tooth Instability,” Proc. 2nd ICFA
Workshop on High Brightness Beams, UCLA, 1999 and preprint SLAC-PUB-8404
(2000).
2. R.L. Warnock, K. Bane and J.A. Ellison, “Simulation of Bunch Lengthening and Sawtooth Mode in SLAC Damping Rings,” Proc. 2000 EPAC, Vienna, to be published.
3. H.S. Dumas, J.A. Ellison and F. Glose, “A Mathematical Theory of Planar Particle
Channeling in Crystals,” Physica D, to be published.
4. D.P. Barber, J.A. Ellison and K. Heinemann, “A Quasiperiodic Treatment of Spin-orbit
Motion in Storage Rings - a New Perspective on Spin Tune,” to appear.
5. J.A. Ellison and K. Heinemann, “Applying Ergodic Theorems to Stroboscopic
Averaging of Liouville Densities and Spin Fields,” to be submitted.
6. T. Sen, J.A. Ellison, I. Vlaicu and M.P. Zorzano, “Fluctuations and the Beam-beam
Interaction in Hadron Colliders,” to be submitted.
Theoretical Support Program for Plasma-Based Concepts for Future High
Energy Accelerators
Thomas Katsouleas, University of Southern California
Summary:
Highlights of our recent work include the following:
• Co-leadership of E-157, a one-meter plasma wakefield accelerator experiment
at SLAC
• Development of the Plasma Afterburner concept
• Design of a new photon accelerator (radiation generation) experiment
• Collective refraction of an electron beam—theory, experiment and simulation
Each of these is described briefly below.
The E-157 Plasma Wakefield Experiment. The goals of this recently completed multiinstitution experiment were to address key issues associated with a 1-10 GeV
accelerator stage based on plasma wakefield acceleration. The experiment used the 30
GeV electron beam at the Stanford Linear Accelerator Center as the driver for a 1.4meter long plasma formed from laser-ionization of a lithium vapor. The experiment
successfully addressed several critical issues for future plasma based accelerators,
including
• Extension of high-gradient plasma acceleration from mm to meter scales
• Detailed study of transverse beam dynamics in a meter-long plasma,
including betatron oscillations, transverse stability and comparisons to beam
envelope models and particle-in-cell (PIC) simulations.
In addition, detailed simulation support was provided to the experiment including some
of the first one-to-one PIC simulations to model experiments without any scaled
parameters (using massively parallel computing at NERSC).
The Plasma Afterburner. A scaling law study we performed last year led to the
identification of an exciting application for the PWFA in high energy physics. Since the
maximum wake amplitude was shown to scale as the inverse of the square of the
bunch length, a ten-fold decrease in bunch length from current SLAC parameters
would enable wake amplitudes exceeding tens of GeV/m. Thus a short plasma section
could be used at the end of SLAC to more than double the energy of a trailing bunch
(formed by over-compressing a single bunch). Combined with strong focusing in the
plasma to provide a small spot size and overcome the loss of luminosity due to the
reduced number in the trailing bunch, we are exploring whether the afterburner
concept could enable the discovery of the Higgs without a major increase in the size of
the SLAC accelerator. We are currently identifying a number of key issues in order for
this scheme to be realizable, and indeed we have had a breakthrough in two areas –
positron acceleration and beam loading. For example, we have found a non-optimized
beam load design that accelerates 1010 particles from 50 to 100 GeV over 7m with 30%
efficiency and 25% energy spread.
Photon Accelerators. When photons are made to “surf” on a plasma wave, they can
gain energy much like particles in an accelerator. In this case their frequency and
hence their energy increases as does their group velocity.
Importance: The wave particle duality and the analogy between light and matter
particles are fundamental to our understanding of nature. This understanding has led
to new radiation sources that may lead to improved wireless communication sources,
radar, etc. A new experiment is being underway to demonstrate a new type of photon
accelerator that could become the highest power THz source in the world (i.e., GWatt).
Collective Refraction of a Beam of Electrons. In a recent experiment at the Stanford
Linear Accelerator Center, a beam of 30 GeV electrons has been shown to refract and
even reflect off of a boundary between dilute plasma and a gas.
Importance: Although refraction of light at an interface is as common as looking
through a glass of water, the similar refraction of particle beams has not been
previously demonstrated. The results are remarkable in that the beam is intense
enough to bore through a mm thick sheet of steel, but bounces off of a dilute layer of
plasma that is one million times less dense than air. This is a result of collective effects
that enhance the refraction in the plasma. The work has now been accepted for
publication and will soon appear in Nature.
Publications:
1. T. Katsouleas, C. Joshi, W. B. Mori, “Plasma Physics with GeV Electron Beams,”
Comments on Modern Physics C 1 (3): 99 (1999).
2. P. Muggli, K. A. Marsh, S. Wang, C. E . Clayton, S. Lee and T. C. Katsouleas,
“Photon-Ionized Lithium Source for Plasma Accelerator Applications,” IEEE Trans.
on Plasma Sci. 27 (3): 791 (1999).
3. H. Suk, C. E. Clayton, G. Hairapetian, C. Joshi, M. Loh, P. Muggli, R. Narang, C.
Pellegrini, J. B. Rosenzweig, and T. C. Katsouleas, “Underdense Plasma Lens
Experiment at the UCLA Neptune Laboratory,” Proceedings of the 1999 IEEE
Particle Accelerator Conference 5: 3708 – 3710 (1999).
4. R. Assmann, P.Chen, F.-J. Decker, R. Iverson, M. J. Hogan, S. Rokni, R. H.
Siemann, D. Waltz, D. Whittum, P. Catravas, S. Chattopadhyay, E. Esarey, W. P.
Leemans, P. Volfbeyn, C. Clayton, R. Hemker, C. Joshi, K. Marsh, W. B. Mori, S.
Wang, T. Katsouleas, S. Lee, and P. Muggli, “Progress toward E-157: A 1 GeV
Plasma Wakefield Accelerator,” IEEE Particle Accelerator Conference 1: 330 -332
(1999).
5. R. G. Hemker, F. S. Tsung, V. K. Decyk, W. B. Mori, S. Lee, and T. Katsouleas,
“Development of a parallel code for modeling plasma based accelerators,” IEEE
Particle Accelerator Conference 5: 3672-3674 (1999).
6. P. Muggli, J. R. Hoffman, K. A. March, S. Wang, C.E. Clayton T. C. Katsouleas, C.
Joshi, “Lithium Plasma Sources for Acceleration and Focusing of Ultra-Relativistic
Electron Beams,” Proceedings of the IEEE Particle Accelerator Conference 5: 3651–
3653 (1999).
7. P. Muggli, J. Yoshii, T. C. Katsouleas, C. E. Clayton, C. Joshi, “Cerenkov Radiation
from a Magnetized Plasma: A Diagnostic for PBWA Experiments,” Proceedings of
the IEEE Particle Accelerator Conference 5: 3654–3656 (1999).
8. A. Ogata and T. Katsouleas, “Proton Acceleration in Plasma Waves Produced by
Backward Raman Scattering,” Proceedings of the IEEE Particle Accelerator
Conference 5: 3713 -3715 (1999).
9. J. L. Hsu, T. Katsouleas, W. B. Mori, C. B. Schroeder, J. S. Wurtele, “Laser
Acceleration in Vacuum,” Proceedings of the IEEE Particle Accelerator Conference
1: 684-686 (1999).
10. K.-C. Tzeng, W. B. Mori, and T. Katsouleas, “Self-trapped Electron Acceleration
from the Nonlinear Interplay between Raman Forward Scattering, Self-focusing,
and Hosing,” Physics of Plasmas 6 (5): 2105 (1999).
11. S. Lee, T. Katsouleas, R. Hemker, and W. B. Mori, “Simulations of a meter-long
plasma wakefield “Simulations of a meter-long plasma wakefield accelerator,”
Phys. Rev. E, June 2000.
12. M. J. Hogan, et al., “E-157: A 1.4 Meter-long Plasma Wakefield Acceleration
Experiment Using a 30 GeV Electron Beam from the Stanford Linear Accelerator
Center Linac,” Phys. Plasmas 7, 224, 2000.
13. S. Lee, et al., "Plasma Wakefield Acceleration of a Positron Beam," submitted to
Phys. Rev. Lett., 2000.
14. T. Katsouleas, W.B. Mori, E. Dodd, S. Lee, R. Hemker, C. Clayton, C. Joshi, E.
Esarey, “Laser Steering of Particle Beams: Refraction and Reflection of Particle
Beams” Nucl. Instrum. Meth. Phys. Res. A, 455: (1) 161-165 Nov 21 2000.
15. M. Ferrario, L. Serafini, T. Katsouleas and I. Ben-Zvi, “Adiabatic Plasma Buncher,”
IEEE Trans Plasma Sci. 28 (4): 1152-8, 2000.
16. A. Ogata and T. Katsouleas, “Proton Acceleration in Plasma Waves Produced by
Backward Raman Scattering,” to appear in Nucl. Inst. Methods, 2000.
17. N. Spence, et al., “Simulations of Cerenkov Wake Radiation Sources,” to be
submitted to IEEE Trans. Plasma Sci., 2000.
18. J. R. Hoffman, et al., “High Power Radiation from Ionization Fronts in a Static
Electric Field in a Waveguide,” to appear in J. Appl. Physics, 2000.
19. P. Muggli, et al., “Collective Refraction of an Electron Beam at a Gas/Plasma
Boundary,” accepted for publication in Nature (February, 2001).
Current Staff:
•
•
•
•
•
•
•
T. Katsouleas
Patrick Muggli
Seung Lee
Jerry Hoffman
Nikolai Spence
Lance Geiger
Mike Penner
PI
Assoc. Research Professor
Graduate Student
Graduate Student
Graduate Student
Undergraduate
Undergraduate
Thomas C. Katsouleas (PI)
University of Southern California
Electrical Engineering Department
Los Angeles, CA 90089-0271
PHONE:
FAX:
E-MAIL:
Website:
213/740-0194
213/740-8677
[email protected]
http://www.usc.edu/dept/engineering/eleceng/plasma_accelerator/
Section 4
Figure 1: Photon accelerator results: (a) experiment showing frequency control of
output radiation and (b) PIC simulation of future experiment to produce high power
THZ radiation.
1.2
P=3 mT, k 0=π/
f=
53 GHz
2
2
1  k 0c ω c,10 ω pe 


+
+
2π  2 2k0 c 2k 0c 
Plasma
93 GHz
1
0.8
d=1 cm
m=-1
Vacuum
d=2 cm
fc=59.1 GHz
m=-2
0.6
0.4
0.2
0
20
THz radiation beaming from plasma
40
60
80
Frequency (GHz)
100
120
Figure 2: Images of the electron beam showing refraction of a portion of the beam: a)
experiment, laser off, b) experiment, laser on at an angle f of 1mrad to the beam, c)
PIC simulation of electron beam, side view with plasma shown (blue), and d) PIC
simulation, head on view corresponding to (b). Cross hairs show undeflected beam
location.
(a)
(b)
Laser off
Laser on
(c)
(d)
Understanding ultimate limits of flux pinning in superconducting
materials for advanced accelerator magnets
Lance Cooley, Applied Superconductivity Center, University of Wisconsin
Summary:
This research program seeks to understand flux-pinning mechanisms and determine
their fundamental limits in superconductors that might be used in a very high-energy
collider. Since the pinning force opposes the outward magnetic pressure of flux lines
in a superconducting solenoid, the ultimate field for any accelerator magnet must be
below the threshold where flux pinning is exceeded. Our work has examined
niobium-titanium alloys, which achieve 3% of the theoretical limit of flux pinning in
accelerator magnet strands, and more recently Nb3Sn, which achieves less than 1%
of its limit but doubles the practical field range of Nb-Ti. We fabricate and analyze
thin films and artificial multilayers because these attain 10-20% of the flux-pinning
limit, have controllable and reproducible morphologies, and can be subjected to a
wide range of characterization. Our recent results suggest that two-dimensional
superconductivity may be crucial to the development of strong flux pinning in Nb-Ti.
Because Nb-Ti contains a laminar mixture of superconducting and nonsuperconducting precipitates at the nanometer scale of quantized flux lines, 2D
properties would greatly enhance the pinning force of the planar interfaces. Nb3Sn
also contains a network of planar flux-pinning sites, but at a length scale 10-100
times larger than that of Nb-Ti. To reduce this length scale, it is necessary to force
Nb3Sn to form very rapidly or constrain its growth. However, these restrictions must
be balanced against the formation of disordered structures, which degrade the
overall properties. We are currently trying to understand how to manage this
balance.
Recent Accomplishments:
We recently published several papers that point to 2D superconductivity in Nb-Ti thin
film multilayers [3-5]. Since we believe that these films are models of the
nanostructure of round wires, an attempt was made to connect these different
regimes by rolling round wires into flat tapes, which aligned the nanostructure with
the tape face [1]. This work was performed as part of the senior project of Anand
Patel. The tapes exhibit 2D behavior similar to that found in the multilayers, which
develops before flux pinning is optimized. This suggests that 2D superconductivity
probably controls the behavior of flux lines as they respond to pinning forces and
external magnetic stresses.
We also recently investigated how to deposit Nb onto bronze substrates to make
Nb3Sn films [2]. When this deposition is carried out at high temperature, the Nb3Sn
reaction occurs rapidly and a thin film with very fine grains results. The peak fluxpinning force of these films is shifted upward in field, as compared to the pinning
force of a control film, due to the higher density of pinning interactions. Since the
control film represents a process similar to that of commercial wires, this experiment
suggests that better pinning efficiency at high field might be gained through
fabrication routes that emphasize rapid Nb3Sn formation. However, the thin films
also exhibited structural disorder, which degraded their properties.
Publications 1999-2000:
1. L. D. Cooley and A. Patel, “Upper critical field anisotropy in Nb-Ti tapes,” submitted
to IEEE Trans. Appl. Supercond.
2. L. .D. Cooley, “Shift of the flux-pinning force curve in Nb3Sn thin films with very fine
grain size,” submitted to IEEE Trans. Appl. Supercond.
3. A. Terentiev, D.B. Watkins, L.E. DeLong, L.D. Cooley, D.J. Morgan, and J.B.
Ketterson, “Periodic magnetization instabilities in a superconducting Nb film with a
square lattice of Ni dots,” Phys. Rev. B 61, R9249-R9252 (2000).
4. L.D. Cooley and C.D. Hawes, L.D. Cooley and C.D. Hawes, “Effect of dimensional
crossover on the upper critical field of practical Nb-Ti alloy superconductors,” J.
Appl. Phys. 86, 5696-5704 (1999).
5. C.D. Hawes, L.D. Cooley, and D.C. Larbalestier, “Dependence of Critical
Temperature and Resistivity of Magnetron Sputtered Nb47wt%Ti on Deposition
Conditions,” IEEE Trans. Appl. Supercond. 9, 1712-1715 (1999).
6. L.D. Cooley, C.D. Hawes, P.J. Lee, and D.C. Larbalestier, “Superconducting
properties and critical current density of Nb-Ti/Ti multilayers,” IEEE Trans. Appl.
Supercond. 9, 1743-1746 (1999).
Current Staff:
Lance Cooley
Tom Thersleff
Undergraduate student
Recent results for Nb3Sn thin films
Very fine grains of
unreacted Nb on film top
1.0
Deposition at 660 °C
4.2 K
6K
8K
10 K
12 K
Fp / Fp max
0.8
Nb3Sn grains
emerging through
top of film
0.6
Shear
0.4
0.2
0.0
0.0
0.2
0.4
0.6
0.8
1.0
H / H*
Fine grains of Nb3Sn formed by rapid
reaction at high deposition temperature
produce a shift of the pinning force curve
toward higher field.
200 nm
Low temperature deposition followed by a
reaction heat treatment produces grain sizes
more typical of wires, and less of a shift of
the pinning-force curve.
1.0
Bronze
Deposition at 400 °C
HT 20 h @ 700 °C
0.8
Fp / Fp max
Fracture cross-section of
thin film
Nb3Sn
4.2 K
6K
8K
10 K
12 K
Flux Shear
0.6
Nb
0.4
1 µm
0.2
0.0
0.0
0.2
0.4
0.6
H / H*
0.8
1.0
SEM backscatter image shows
composition variations as
contrast variations. Tin-rich and
tin-poor Nb3Sn layers are visible.
1 µm
High Field Superconductor Development and Understanding:
Flux Pinning, High Field Current Density and Novel Fabrication Processes for Probing the Limits of Performance in High Field Superconductors
David C. Larbalestier and Peter J. Lee – University of Wisconsin-Madison
Summary:
I.
DESCRIPTION
The Applied Superconductivity Center is the leading university center in the world for the study
of superconducting strand. It has both a complete wire fabrication facility (including hydrostatic
extrusion) and the facilities to fully characterize the strand for superconducting properties.
Combining our own light microscope and high-resolution image analysis capabilities with the
adjacent electron microscope facilities of UW Integrated Microscopy Resource, we can completely characterize the microstructural properties of the strands. Undergraduates and graduate
students in our center obtain hands-on experience in all areas of strand fabrication and characterization. Not surprisingly graduates from our program working in industry have played an
important part in the development of high performance commercial strand.
Under our High Energy Physics program we work with the accelerator community to improve
the performance of superconductors for application in accelerator magnets. The center has
played a leading role in the development of accelerator strand since the Tevatron Energy Saver
Strand. In 1991 the Institute of Electrical and Electronic Engineers (Nuclear and Plasma Society) recognized the importance of this work by awarding Prof. David Larbalestier (jointly with
R. M. Scanlan) the Particle Accelerator Conference Award for the development of High Current
density Nb-Ti conductors for Accelerator Magnets.
The current aim of the program is to develop new high field superconductors for application in
accelerator magnets of the type required for future hadron and muon colliders. We focus on
understanding the factors controlling the critical current density and upper critical field performance of Nb-Ti, Nb3Sn, and Nb3Al conductors and then devise processing strategies to incorporate the most favorable properties into conductors of these materials. A unique feature of
the work is the alliance of detailed, local microstructural characterization and local electromagnetic characterization using very sensitive vibrating sample magnetometer and specific heat
measurements to reveal the compositional sensitivity of the properties. The center organizes
the superconductor material workshops that have so strongly stimulated the community
working on accelerator applications of superconductors. The center also provides information
to the community via its website at: http://www.asc.wisc.edu/. We are an active member of
the new Conductor Development Program designed to facilitate the commercial production of
high performance superconductor for the next generation of high energy physics applications.
II.
PUBLICATIONS 1999-AUGUST 2000:
1. C. D. Hawes, P. J. Lee, and D. C. Larbalestier, "Measurement of the Critical Temperature Transition and Composition Gradient in Powder-In-Tube Nb3Sn Composite Wire,"
IEEE Transactions on Applied Superconductivity, 10(1): 988-991, 2000.
2. P. J. Lee and D. C. Larbalestier, "Position Normalization as a Tool to Extract Compositional and Microstructural Profiles from Backscatter and Secondary Electron Images,"
submitted for publication in proceedings of Microscopy & Microanalysis 2000, Philadelphia, PA, August 13, 2000.
3. P. J. Lee, A. A. Squitieri, and D. C. Larbalestier, "Nb3Sn: Macrostructure, Microstructure,
and Property Comparisons for Bronze and Internal Sn Process Strands," IEEE Transactions on Applied Superconductivity, 10(1): 979-982, 2000.
4. M. T. Naus, P. J. Lee, and D. C. Larbalestier, "The Interdiffusion of Cu and Sn in Internal Sn Nb3Sn Superconductors," IEEE Transactions on Applied Superconductivity, 10(1):
983-987, 2000.
5. L. D. Cooley and L. R. Motowidlo, "Advances in High-Field Superconducting Composites
by Addition of Artificial Pinning Centres to Niobium-Titanium," Superconductor Science
& Technology, 12: R135-R151, 1999.
6. L. D. Cooley, C. D. Hawes, P. J. Lee, and D. C. Larbalestier, "Superconducting Properties and Critical Current Density of Nb-Ti/Ti Multilayers," IEEE Transactions on Applied
Superconductivity, 9(2): 1743-1746, 1999.
7. L. D. Cooley and C. D. Hawes, "Effect of a Dimensional Crossover on the Upper Critical
Field of Practical Nb-Ti Alloy Superconductors," Journal of Applied Physics, 86(10):
5696-5704, 1999.
8. C. D. Hawes, L. D. Cooley, and D. C. Larbalestier, "Dependence of Critical Temperature
and Resistivity of Thin Film Nb47wt%Ti on Magnetron Sputtering Conditions," IEEE
Transactions on Applied Superconductivity, 9(2): 1712-1715, 1999.
9. D. C. Larbalestier and P. J. Lee, "Prospects for the Use of High Temperature Superconductors in High Field Accelerator Magnets," in proceedings of IEEE Particle Accelerator
Conference, New York, A. Luccio and W. MacKay, eds., March 30, 1999, pp. 177-181.
10. P. J. Lee, "Abridged Metallurgy of Ductile Alloy Superconductors," in J. G. Webster, ed.,
"Wiley Encyclopedia of Electrical and Electronics Engineering," vol. 21, pp. 75-87, New
York: John Wiley & Son, Inc., 1999.
11. P. J. Lee, C. M. Fischer, W. Gabr-Rayan, D. C. Larbalestier, M. T. Naus, A. A. Squitieri,
W. L. Starch, E. Z. Barzi, P. J. Limon, G. Sabbi, A. Zlobin, H. Kanithi, S. Hong, J. C.
McKinnell, and D. Neff, "Development of High Performance Nb-Ti(Fe) Multifilamentary
Superconductor for the LHC Insertion Quadrupoles," IEEE Transactions on Applied Superconductivity, 9(2): 1559-1562, 1999.
12. P. J. Lee, C. M. Fischer, D. C. Larbalestier, M. T. Naus, A. A. Squitieri, W. L. Starch, R. J.
Werner, P. J. Limon, G. Sabbi, A. Zlobin, and E. Gregory, "Development of High Performance Multifilamentary Nb-Ti-Ta Superconductor for LHC Insertion Quadrupoles,"
IEEE Transactions on Applied Superconductivity, 9(2): 1571-1574, 1999.
13. P. J. Lee, A. A. Squitieri and D. C. Larbalestier, "Nb3Sn: Macrostructure, Microstructure,
and Property Comparisons for Bronze and Internal Sn Process Strands," IEEE Transactions on Applied Superconductivity, 10(1): 979-982, 2000.
14. C. D. Hawes, P. J. Lee, and D. C. Larbalestier, "Measurement of the Critical Temperature Transition and Composition Gradient in Powder-In-Tube Nb3Sn Composite Wire," C.
D. Hawes, P. J. Lee, and D. C. Larbalestier, IEEE Transactions on Applied Superconductivity, 10(1): 988-991, 2000.
15. M. T. Naus, P. J. Lee, and D. C. Larbalestier, "The Interdiffusion of Cu and Sn in Internal Sn Nb3Sn Superconductors," IEEE Transactions on Applied Superconductivity, 10(1):
983-987, 2000.
P. J. Lee and D. C. Larbalestier, "Position Normalization As A Tool To Extract Compositional
And Microstructural Profiles From Backscatter And Secondary Electron Images," Microscopy and Microanalysis, 6, Supplement 2, pp. 1026-1027, 2000.
III.
INVITED TALKS AND SEMINARS 2000 ONLY
1. D. C. Larbalestier, “Critical Currents: Just How Critical Are They?” Applied Superconductivity Conference (ASC), Virginia Beach, VA -Plenary
2. P. J. Lee, "Superconductor status and prospects," VLHC Annual Meeting
3. D. C. Larbalestier, “Influence of HTS Grain Boundaries on Critical Current Density,” 6th
International Conference on Materials and Mechanisms of Superconductivity and High
Temperature Superconductors (M2S-HTSC-VI), Houston, TX
4. D. C. Larbalestier, 7th Annual International Conference on Composites Engineering
(ICCE/7), Denver, CO
5. D. C. Larbalestier, “Buffer Layers” DOE Wire Development Workshop, St. Petersburg, FL
6. D. C. Larbalestier, SCENET Topical Workshop on Coated Conductors, Gottingen, Germany
Current Staff:
Principal Investigator:
Prof. David Larbalestier
Co-Principal Investigator: Dr. Peter Lee
[email protected]
[email protected]
Staff:
•
Dr. Alexander Gurevich:
•
•
Alex Squitieri:
Bill Starch:
•
Orrie Lokken:
Theory of flux pinning and the phenomenology of superconductors
Magnet facility development and supervision.
Fabrication laboratory supervision and strand fabrication
and characterization.
Additional support for magnet facility
Graduate Student:
• Chad Fischer
Undergraduate Students:
• Matt Jewell
• Danica Christensen
Graduates from ASC from this contract in 1999-2000:
• Christopher Hawes
SE2
SE2
14 T VSM/CMP
FESEM Images of PIT Nb33Sn
Sn Nucleation Layer
Layer
1
1 µm
µm
BEI
BEI
1
1 µm
µm
18
Critical Temperature (K)
SE2
SE2
1
1 µm
µm
SEI-Fracture
SEI-Fracture
1
1 µm
µm
16
SMI Binary PIT 675 °C HT
14
10
8
4
0.0
Critical Current Density, A/mm²
12000
1994
1991
10000
8000
1986
6000
1985
4000
1980
2000
0
0
1
2
3
4
5
6
Applied Field, T
7
8
4 Hours
6 Hours
8 Hours
16 Hours
32 Hours
47 Hours
64 Hours
147 Hours
263 Hours
0.1
0.2
rf
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Normalized distance from shielded core to filament edge (rs/c/rf)
MFTF Conductor
Tevatron Energy Saver Strand, 1980.
Best Production High Homogeneity, 1985.
Best Univ.-WI HT Multi-Fil. Composite, '85.
Best Small Scale HT Multi-Fil. Composite '86
Revised Equivalent SSC Strand Specification
Nb-Ti: Best Industrial Scale HT Composites 1990
Aligned ribbbons, field parallel to ribbons.
Furukawa APC '94, dp=10.5nm
Supercon APC/HT '95
14000
rS/C
12
6
Advancement in the Critical Current Density of Nb-Ti Based
Superconducting Strand at 4.2K
Tc Profiles
9
10
Oxford Instruments
15/17T Magnet
Research activity report from the Advanced Accelerator R&D
Summary:
W. Gai - Argonne National Laboratory.
The advanced accelerator research program at Argonne National Laboratory
concentrates on advancing the physics and technologies of beams, in particular, new
approaches to beam acceleration and instrumentation important to the high energy
physics program. Our present focus is on wakefield acceleration, a method that uses
intense electron beams to power future linear colliders. A charged particle bunch
traversing a structure or plasma generates an electromagnetic field termed a wakefield.
Under some conditions the resulting electric fields are very intense and can be used to
accelerate other charged particles. Our main activities are the study of: advanced
acceleration structures, dielectric wakefield acceleration (DWFA) and two beam
acceleration (TBA); plasma wakefield acceleration (PWFA) and focusing; and high
current, short pulse electron beam generation, acceleration and propagation.
We are operating a very unique facility. The Argonne Wakefield Accelerator (AWA)
produces a high charge (10 – 100 nC), short pulse (10 – 40 ps) electron beam with an
energy of 15 MeV to drive the wakefield and a second, low charge (0.5 nC), short pulse
(8 ps) electron beam with an energy of 4 MeV to probe the wakefield. This facility is
based on advanced RF photoinjector technology. A high power, single shot, UV laser is
used for electron beam production. This facility has been in operation for the past 5
years with significant experimental results accomplished as list below:
• First ever 100 nC RF photocathode gun and Linac; first ever PWFA in underdense
regime (non-linear); first ever dielectric TBA experiment; first multi-moded dielectric
wakefield experiment.
• Development of dielectric based acceleration structures, such as the step-up
transformer for two-beam acceleration, and an externally RF powered, travelling
wave accelerator.
• Commissioned the TESLA Test Facility (TTF) photoinjector.
• Multiple drive beam generation (bunch train) and its applications to dielectric TBA
and collinear wakefield acceleration.
The above experiments have produced many publications. The AWA users include:
UCLA, JPL, FNAL, APS, KSU and IIT.
Most recent activities:
AWA drive beam RF photocathode gun upgrade
We are currently making a major effort to improve the drive beam quality by
constructing a third generation drive gun. This new gun is a 1 ½ cell RF photocathode
gun. Based on numerical simulations, it should produce a low emittance (20 times
lower than present) and a short bunch length (3 – 4ps) for the same charge intensities
as the current drive gun. Other upgrades will consist of vacuum improvements and
new cathode materials. We intend to replace the current Mg cathode with a high QE,
CsTe type cathode. Using this third generation drive gun and the current AWA laser
system (5 mJ, 4ps @ 248 nm), we will be able to produce a pulse train of 4 pulses
at100 nC each. This pulse train could easily achieve 100 MV/m acceleration gradient
using the same dielectric TBA (step-up transformer) structure as used in our most
experiment. The new gun could also produce up to 64 pulses at 40 nC each. This gun
is already machined, brazed and vacuum tested. It is currently undergoing fine tuning
and will be installed in the AWA tunnel next month.
Experimental demonstration of dielectric two-beam acceleration ("dielectric TBA") using
the dielectric step-up transformer.
Recently, we have made significant progress toward the demonstration of dielectric TBA
as a practical high energy physics accelerator by using a dielectric step-up transformer.
Our recent proof of principle experiment clarified the associated physics and
engineering issues such as RF coupling and acceleration into the correct acceleration
mode. Using a single, high-charge beam, we have generated and extracted a high
power RF pulse from a 7.8 GHz primary dielectric structure and subsequently pulse
compressed this power into a second accelerating structure with higher dielectric
constant and smaller transverse dimensions. We have measured the energy change of
a second (witness) beam passing through the acceleration stage. The measured
acceleration gradient is > 4 times the deceleration gradient. Detailed wakefields in the
secondary dielectric structure have been systematically studied. Using the new electron
gun described above and the same step-up transformer, we will not only achieve 100
MV/m, but also could accelerate the beam to a net energy gain of 100 MeV in less than
a meter. This is the equivalent of powering the secondary structure with a 500 MW
external RF power source of 50 ns pulse length.
Development of X-band dielectric based travelling-wave accelerator
Significant progress was also made in the area of advanced acceleration structure
development, in particular, in the construction and testing of an X-band dielectric
acceleration structure. A technical breakthrough was made in the area of RF coupling
between a hollow, rectangular waveguide and a cylindrical, dielectric structure using a
combination of a tapered dielectric end section and a carefully adjusted coupling slot.
Both network analyzer and vacuum test bench test have been performed. Network
analyzer measurements demonstrated a power coupling efficiency in excess of 95% and
a bandwidth of 30 MHz. Vacuum tests showed that this dielectric loaded structure can
be operated in an ultra-high vacuum environment. Bench test measurements agree
with MAFIA simulations to within the limits of the approximations used. High power
tests using a high power klystron at SLAC and a magnicon at NRL are planned for the
very near future. These high power tests should answer some of the critical questions
about dielectric based acceleration, such as RF breakdown and Joule heating, etc.
In addition to the above activities, we have also performed the first ever coherent
transition/Cherenkov microwave radiation experiment (with JPL/UCLA) to simulate
cosmic ray showers. Another significant result obtained recently was the theoretical
study and experimental demonstration of the physics of multiple beam driven,
multimoded wakefield phenomena.
Current Staff:
•
•
•
•
•
Gai, W
Conde, M
Schoessow, P
Zou, P
Power, J.
Scientist
Scientist
Scientist
Scientist
Wei Gai (PI)
Argonne National Laboratory
9700 S. Cass Avenue 362 F124
Argonne, IL 60439
PHONE: 630-252-6560
Advanced Accelerator R&D at ANL
Research
facility: High charge, high current facility for wakefield acceleration.
Advanced structure and acceleration research
7.8 GHz Step up transformer used for
first ever observation dielectric two
beam acceleration
Dielectric wakefield accelerator
before assembled.
X-band dielectric traveling accelerator ready
for high power test.
First ever observation of non-linear plasma
wakefield acceleration and focusing in
blowout regime
BNL Accelerator Test Facility
Ilan Ben-Zvi, Brookhaven National Laboratory
Summary:
The Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL) has been
in operation since 1992. The ATF is the nation's only experimental facility operated for
accelerator scientists as a proposal-driven, program-committee reviewed users facility.
The ATF Program Committee is also serving as a Steering Committee for the BNL
Center for Accelerator Physics, (CAP). The membership of the ATF Program Committee
comprises of blue-ribbon accelerator scientists from universities and national
laboratories. It was first chaired by Andrew Sessler (Lawrence Berkeley National
Laboratory), and then by Maury Tigner (Cornell University), followed by Robert Siemann
(Stanford Linear Accelerator Center) and currently by Chan Joshi (University of
California at Los Angeles).
In the first few years of the ATF, the number of experiments grew rapidly. Later on the
number reached a steady state, with experiments retiring at about the same rate as
experiments were being approved. This can be seen in Figure 1.
At the same time the complexity, sophistication and cost of the experiments continues
to grow. The cost of some of the experiments runs in the millions of dollars, provided
at times by multi-institutional collaborations. The growth of the scientific activity let to a
lot of published results and invited papers in meetings. The number of publications vs.
year can be seen in Figure 2.
We at the ATF take pride also in the contribution we provide to the education of
graduate students and post docs in accelerator physics. ATF students come from all
across the nation, from Ivy League schools to large State Universities and small
colleges. The number of students graduating per year and the cumulative number of
graduations is shown in Figure 3. The distribution of 17 students (alumni and current
students) is shown in Figure 4.
As a by-product of the R&D to improve the beam brightness, the ATF became a worldleader in the development of laser photocathode RF guns (photoinjectors). The ATF
initial gun made its way to France, CERN, Rocketdyne Inc. and UCLA. The second gun,
developed as a CRADA with Grumman powered a compact FEL at Princeton and a laser
- beam chemical research facility at BNL. The third generation gun made its way to
SLAC, UCLA and BNL, and the fourth one is in ANL, BNL and Japan. At the same time
the science of metal photocathode was pushed to new heights at BNL with copper,
magnesium and niobium cathodes providing high quantum efficiency and long lifetimes.
Significant Experiments Completed this year: Staged Electron Laser Accelerator, HighGain Harmonic-Generation FEL, and Compton Scattering of Laser on Beams.
Publications:
1. P. Catravas, W.P. Leemans, J.S. Wurtele, M.S. Zolotorev, M. Babzien, I. Ben-Zvi, Z.
Segalov, X.J. Wang, and V. Yakimenko, “Measurement Of Electron Beam Bunch
Length And Emittance Using Shot Noise-Driven Fluctuations In Incoherent
Radiation,” Phys. Rev. Lett. 82 no. 26, 5261, (1999)
2. S. Kashiwagi, M. Washio, T. Kobuki, R. Kuroda, I. Ben-Zvi, I. Pogorelsky, K. Kusche,
J. Skaritka, V. Yakimenko, X.J. Wang, T. Hirose, T. Muto, K. Dobashi, J. Urakawa, T.
Omori, T. Okugi, A. Tsunemi, D. Cline, Y. Liu, P. He, and Z. Segalov, “Observation of
High Intensity X-rays in Inverse Compton Scattering Experiment,” International
Symposium on New Visions in Laser-Beam Interactions, Tokyo Metropolitan
University, Tokyo Japan, October 11-15, 1999. BNL 66934
3. I. V. Pogorelsky, I. Ben-Zvi, X. J. Wang and T. Hirose, “Femtosecond Laser
Synchrotron Sources Based On Compton Scattering In Plasma Channels,” Nuclear
Instrum. & Methods A, October 1999. BNL 66933
4. I. V. Pogorelsky, N. E. Andreev, and S. V. Kuznetsov, "Monochromatic Laser
Wakefield Acceleration", Proceedings of LASERS' 98, Tucson, Arizona, December 711, 1998, STS Press, McLean (1999), p. 898
5. I. V. Pogorelsky, I. Meshkovsky, A Dublov, I. Pavlishin, Yu. A. Boloshin, G. B.
Deineko, and A. Tsunemi "Optical Design And Modeling Of The First Picosecond
Terawatt CO2 Laser At The BNL ATF," Proceedings of LASERS' 98, Tucson, Arizona,
December 7-11, 1998, STS Press, McLean (1999), p. 911
6. X.J. Wang, S.V. Milton, N.D. Arnold, C. Benson, S. Berg, W. Berg, S.G. Biedron, Y.C.
Chae, E.A. Crosbie, G. Decker, B. Deiry, R.J. Dejus, P. Den Hartog, R. Dorwegt, M.
Edrmann, Z. Huang, H. Friedsam, H.P. Freund, J.N. Galayda, E. Gluskin, G.A.
Goeppner, A. Grelick, J. Jones, Y. Kang, K.-J. Kim, S. Kim, K. Kinoshita, R. Lill, J.W.
Lewellen, A.H. Lumpkin, G.M. Markovich, O. Makarov, E.R. Moog, A. Nassiri, V.
Ogurtsov, S. Pasky, J. Power, B. Tieman, E. Trakhtenberg, G. Travish, I. Vasserman,
N. Vinokurov, D.R. Walters, J. Wang, B. Yang and S. Xu, “The FEL Development at
the Advanced Photon Source,” Reprinted From: Free-Electron Laser Challenges II,
Proceedings of SPIE Reprint, pgs. 86-95, January 1999. BNL - 66945 Reprint
PAC'99 Invited Papers:
1.
X. J. Wang, “Producing And Measuring Small Electron Bunches,” Proc. of the
1999 Particle Accelerator Conference, A. Luccio, W. MacKay, Editors, 229, (1999)
2.
V. Balakin, A. Bazhan, P. Lunev, N. Solyak, V. Vogel, P. Zhogolev, A. Lisitsyn, and
V. Yakimenko, “Experimental Results From A Microwave Cavity Beam Position
Monitor,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W.
MacKay, Editors, 461, (1999)
PAC'99 other papers:
1. W. D. Kimura, L. P. Campbell, S. C. Gottschalk, D. C. Quimby, K. E. Robinson, L. C.
Steinhauer, M. Babzien, I. Ben-Zvi, J. C. Gallardo, K. P. Kusc He, I. V. Pogorelsky, J.
Skaritka, A. Van Steenbergen, V. Yakimenko, D. B. Cline, P. He, Y. Liu, R. B. Fiorito,
R. H. Pantell, D. W. Rule, and J. Sandweiss, “Progress on STELLA Experiment,” Proc.
of the 1999 Particle Accelerator Conference, A. Luccio, W. MacKay, Editors, 3722,
(1999). BNL 66960.
2. X.J. Wang. I. Ben-Zvi, J. Sheehan and V. Yakimenko, “Brookhaven Accelerator Test
Facility 100 MeV Energy Upgrade,” Proc. of the 1999 Particle Accelerator
Conference, A. Luccio, W. MacKay, Editors, 3495, (1999)
3. T. Srinivasan-Rao, I. Ben-Zvi, K. Batchelor, J. P. Farrell, and J. Smedley, “Simulation,
Generation, and Characterization of High Brightness Electron Source at 1 GV/m
Gradient,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W. MacKay,
Editors, 75, (1999), BNL 66464
4. Y. Aoki, J. Yang, M. Yorozu, Y. Okada, A. Endo, T. Kozawa, Y. Yoshida, S. Tagawa,
M. Washio, X. Wang, and I. Ben-Zvi, “A High-duty 1.6 Cell s-Band RF Gun Driven By
a psec Nd:YAG Laser,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio,
W. MacKay, Editors, 2018, (1999)
5. M. Babzien, I. Ben-Zvi, R. Malone, X.-J. Wang, and V. Yakimenko, “Recent progress
in emittance control of the photoelectron beam using transverse laser shape
modulation and tomography technique,” Proc. of the 1999 Particle Accelerator
6. Li-Hua Yu, Marcus Babzien, Ilan Ben-Zvi, Adnan Douryan, Bill Graves, Erik Johnso n,
Sam Krinsky, Robert Malone, Igor Pogorelsky, John Skaritka, George Rakowsky, L.
Solomon, Xijie Wang, Marty Woodle, Vitaly Yakimenko, Sandra Biedron, John
Galayda, Isaac Vasserman and Vadim Sajaev, “The Status of the High-Gain
Harmonic Generation Free-Electron Laser Experiment at the Accelerator Test
Facility,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W. MacKay,
Editors, 2471, (1999)
7. A. Murokh, P. Frigola, P. Musumeci, C. Pellegrini, J. Rosenzweig, A. Tremaine, M.
Babzien, I. Ben-Zvi, A. Doyuran, E. Johnson, J.Skaritka, X.J.Wang, K.A.Van Bibber,
J.M.Hill, G.P. Le Sage, D. Nguyen and M. Cornacchia, “Photon Beam Diagnostics for
the VISA FEL,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W.
8. A. Tsunemi, A. Endo, I. Pogorelsky, I. Ben-Zvi, K. Kusche, J. Skaritka, V. Yakimenko,
T. Hirose, J. Urakawa, T. Omori, M. Washio, Y. Liu, P. He, and D. Cline, “Ultra-Bright
X-Ray Generation Using Inverse Compton Scattering of Picosecond CO2 Laser
Pulses,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W. MacKay,
Editors, 2552, (1999). BNL 66961.
9. L.H. Yu, “Design Parameters Of The High Gain Harmonic Generation Experiment
Using Cornell Undulator At The ATF,” Proc. of the 1999 Particle Accelerator
10. V. Sajaev, Li-Hua Yu, A. Douryan, R. Malone, X. Wang, and V. Yakimenko,
“Diagnostics And Correction Of The Electron Beam Trajectory In The Cornell Wiggler
At The Accelerator Test Facility,” Proc. of the 1999 Particle Accelerator Conference,
A. Luccio, W. MacKay, Editors, 2942, (1999)
11. S.G. Biedron, G.A. Goeppner, J.W. Lewellen, S.V. Milton, A. Nassiri, G. Travish, X.J.
Wang, N.D. Arnold, W.J. Berg, M. Babzien, C.L. Doose, R.J. Dortwegt, A. Grelick,
J.N. Galayda, G.M. Markovich, S.J. Pasky, J.G. Power, and B.X. Yang, “The Operation
Of The BNL/ATF Gun-Iv Photocathode rf Gun At The Advanced Photon Source,”
Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W. MacKay, Editors,
2024, (1999)
12. J.-M. Fangy, T.C. Marshall, J.L. Hirshfield, M.A. LaPointe, T-B. Zhang, and X.J.
Wang, “An Experimental Test Of The Theory Of The Stimulated Dielectric WakeField Accelerator,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W.
13. Y.K. Semertzidis, V. Castillo, R.C. Larsen, D.M. Lazarus, B. Magurnoz, T. SrinivasanRao, T. Tsang, V. Usack, L. Kowalski, and D.E. Kraus, “Electro-Optical Detection Of
Charged Particle Beams,” Proc. of the 1999 Particle Accelerator Conference, A.
Luccio, W. MacKay, Editors, 490, (1999)
14. R. Ruland, D. Arnett, G. Bowden, R. Carr, B. Dix, B. Fuss, C. Le Cocq Z. Wolf, J.
Aspenleiter, G. Rakowsky, J. Skaritka, P. Duffy, and M. Libkind, “Alignment Of The
VISA Undulator,” Proc. of the 1999 Particle Accelerator Conference, A. Luccio, W.
15. G. Rakowsky, J. Aspenleiter, L. Solomon, R, Carr, R. Ruland and S. Lidia,
“Measurement and Optimization of The VISA Undulator,” Proc. of the 1999 Particle
Accelerator Conference, A. Luccio, W. MacKay, Editors, 2698, (1999), BNL 66499.
16. M. Libkind, L. Bertolini, P. Duffy, R. Carr, G. Rakowsky, and J. Skaritka, “Mechanical
Design Of The VISA Undulator,” Proc. of the 1999 Particle Accelerator Conference,
A. Luccio, W. MacKay, Editors, 2477, (1999)
17. L.-H. Yu, M. Babzien, I. Ben-Zvi, L.F. DiMauro, A. Doyuran, W. Graves, E. Johnson,
S. Krinsky, R. Malone, I. Pogorelsky, J. Skaritka, G. Rakowsky, L. Solomon, X.J.
Wang, M. Woodle, V. Yakimenko, S.G. Biedron, J.N. Galayda, E. Gluskin, J. Jagger,
V. Sajaev and I. Vasserman, “First Lasing Of A High-Gain Harmonic Generation FreeElectron Laser Experiment,” Nucl. Instr. and Meth. A 445, 301, (2000) BNL 66792.
18. I. Ben-Zvi, J. Kewisch, J. Murphy and S. Peggs, "Accelerator Physics Issues in
eRHIC", To be published in NIM-A.
19. L.-H. Yu, M. Babzien, I. Ben-Zvi, L.F. DiMauro, A. Doyuran, W. Graves, E. Johnson,
S. Krinsky, R. Malone, I. Pogorelsky, J. Skaritka, G. Rakowsky, L. Solomon, X.J.
Wang, M. Woodle, V. Yakimenko, S.G. Biedron, J.N. Galayda, E. Gluskin, J. Jagger,
V. Sajaev, and I. Vasserman, “High-Gain Harmonic-Generation Free-Electron Laser,”
Science, 289 (2000) 932
20. L. P. Campbell, C. E. Dilley, S. C. Gottschalk, W. D. Kimura, † D. C. Quimby, L. C.
Steinhauer, M. Babzien, I. Ben-Zvi, J. C. Gallardo, K. P. Kusche, I. V. Pogorelsky, J.
Skaritka, A. van Steenbergen, V. Yakimenko, D. B. Cline, P. He, Y. Liu, and R. H.
Pantell, “Inverse Cerenkov Acceleration Experimental Results for Staged Electron
Laser Acceleration,” To be published in IEEE Transactions on Plasma Science,
Special Issue on Second Generation Plasma and Laser Accelerators.
21. M. Ferrario, T. C. Katsouleas, L. Serafini and I. Ben Zvi, Adiabatic Plasma Buncher,
To be published in IEEE Transactions on Plasma Science, Special Issue on Second
Generation Plasma and Laser Accelerators.
22. A. Murokh, J. Rosenzweig, V. Yakimenko, E. Johnson, and X.J. Wang, “Limitations
On The Resolution Of YAG:Ce Beam Profile Monitor For High Brightness Electron
Beam,” to be published in World Scientific.
23. I.V. Pogorelsky, I. Ben-Zvi, T. Hirose, S. Kashiwagi, V. Yakimenko, K. Kusche, P.
Siddons, J. Skaritka, A. Tsunemi, T. Omori, J. Urakawa, M.Washio and T. Okugi,
“Demonstration of 7x10**18 photons/second peaked at 1.8 Å in relativistic Thomson
scattering experiment,” Submitted to PR ST AB.
24. Doyuran, M. Babzien, T. Shaftan, L.-H. Yu, I. Ben-Zvi, L. F. DiMauro, W. Graves, E.
Johnson, S. Krinsky, R. Malone, I. Pogorelsky, J. Skaritka, G. Rakowsky, X.J. Wang,
M. Woodle, V. Yakimenko, S. G. Biedron, J.N. Galayda, E. Gluskin, J. Jagger, V.
Sajaev, and I. Vasserman, "New Results Of The High-Gain Harmonic Generation
Free- Electron Laser Experiment," Proceedings
Conference, Duke University (2000)
Current Staff:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Ben-Zvi, I.
Wang, X.J.
Yakimenko, V.
Pogorelsky, I.
Malone, R.
Babzien, M.
Montemagno, M.
Harrington, R.
Zhou, F.
Tremaine, A.
Kashiwagi, S.
Chang, X.
Kusche, K.
Murokh, A.
Doyuran, A.
Biedron, S.
PI
Deputy
Accelerator Physicist
Laser Physicist
Senior Computer Analyst
Laser Engineer
Electronic Technician
Mechanical / Laser Technician
Post Doctoral Fellow
Research Collaborator
Staff Engineer
Ph.D. Student, UCLA
Ph.D. Student, Stony Brook
Ph.D. Student, Lund
Ilan Ben-Zvi (PI)
Brookhaven National Laboratory
MS 725C
Upton NY 11973
PHONE:
631/344-5143
FAX:
631/344-3029
E-MAIL:
[email protected]
Website:
http://www.atf.bnl.gov
of
2000
International
FEL
Montage:
ATF publications
ATF Experiments
50
40
15
30
10
20
5
10
0
0
Year
Year
Figure1. The number of ATF experiments as a function of time.
Figure 2. The number of ATF publications as a function of year of publication, from
1990 to 1999.
ATF students by school
ATF Graduating Students
15
Princeton
6%
UCLA
24%
10
5
0
1992 1993 1994 1995 1996 1997 1998 1999
Year
Stanford
6%
Columbia
New
6%
Mexico
6%
Stony
Brook
34%
MIT
12%
Dartmout
h
6%
Figure 3. Graduate students by year of graduation (yellow) and cumulative total (red).
Figure 4. The distribution of 17 ATF graduate students by school.
Brookhaven National Laboratory Magnet Program
M. Harrison – Brookhaven National Laboratory
Summary:
The Superconducting Magnet Division (SMD) at Brookhaven National Laboratory (BNL)
is developing novel magnet designs and bringing new technologies to future high field
magnets. In particular, BNL has taken the initiative in developing accelerator magnets
with High Temperature Superconductors (HTS) using racetrack coils. This could change
the future of accelerator magnets and accelerator operation. The present magnet
program also includes an efficient R&D approach for studying issues and ideas in a
systematic and low cost manner.
HTS and Nb3Sn superconductors hold the key to attaining high fields in future magnets.
However, these conductors are brittle in nature. The conventional cosine theta designs
put a significant restriction on how these conductors can be used in a magnet.
Therefore, alternate conductor friendly racetrack coil designs with large bend radius
have been developed at BNL to overcome the limitations posed by the brittle nature of
these conductors. These magnet designs are also better able to accommodate the large
Lorentz forces associated with high fields. Moreover, these designs and construction
techniques are expected to be scaleable for large-scale, economic production of the
magnets. These designs allow the use of “React and Wind” technology where a brittle
pre-reacted cable is used in winding coils. This puts many fewer restrictions on the
materials that can be used in making coils. Moreover, the required temperature
regulation for reacting HTS materials means that the “React and Wind” technology must
be used in making magnets with them.
BNL has been making racetrack coils magnets using HTS and Nb3Sn tapes for several
years. Recently, BNL has started making similar magnets with cable as well. It has
made two 10-turn coils with HTS cable and three 10-turn coils using pre-reacted Nb3Sn
cable. The brittle pre-reacted Nb3Sn cable was insulated and the coil was wound using
facilities and procedures similar to those used in the conventional NbTi magnets.
According to the conventional wisdom, one would have expected a large degradation in
performance as the cable was subjected to a large strain. The two Nb3Sn coils were
tested in the common coil magnet configuration and the magnet reached plateau only
after one quench at about 4 T. Based on earlier data on the cable degradation, the
additional degradation in the magnet was less than 10%.
The reasonable performance of the first magnet (one training quench, relatively small
degradation) augurs well for the future of “React and Wind” common coil magnet
technology. By the very nature of the 10-turn coil program, it should be possible to
systematically find out the source of degradation. The two coils made with HTS are
ready for test. They will be tested in October 2000.
For a muon collider and neutrino storage ring BNL is designing magnets with sufficient
gap at the midplane that the muon decay products in the midplane do not hit the
superconducting coils. The upper and lower coils are enclosed in separate cryostats,
and the yoke iron is warm. For a compact ring, a combined function dipole design is
being developed. It has a skew quadrupole rather than the normal quadrupole
component of the conventional combined function magnet. These designs do not
require the use of a tungsten liner in the magnet aperture.
BNL has a diverse magnet program. In addition to the program described above, it is
examining rapid cycling superconducting magnets. Moreover, BNL is also looking into
the application of the superconducting technology developed for accelerator magnets to
other areas such as biological and medical sciences. It continues R&D on
superconducting material and cable characterization.
Michael Harrison
Brookhaven National Laboratory
MS 902A
Upton NY 11973
PHONE:
631/344- 7173
PHONE:
631/344- 6122
FAX:
631/344-2190
E-MAIL:
[email protected]
Fermilab Advanced Accelerator Magnet and Superconductor R&D Programs
G.W. Foster, P.J. Limon and A.V. Zlobin - FNAL
Summary:
Superconducting (SC) magnet R&D at Fermilab has two major programs with a common
strategic goal: the construction of a future hadron collider at the ultra-high energies only
available with a SC proton synchrotron. The first program targets high field magnets
with advanced superconductors to obtain the highest possible energy in a fixed-size
tunnel. The second program concentrates on low field magnets designed to provide the
lowest cost per unit bend field using conventional materials. Both magnet types are an
essential feature in a staged approach to ultra-high energies in which an initial “entrylevel” machine based on low field magnets in a large tunnel is used to recapture the
energy frontier in America. High field magnets in the same tunnel would eventually allow
attainment of far higher energies in a series of affordable steps which provide a healthy
and exciting future for high energy physics.
The development and study of a single bore cos-theta dipole models for future
accelerators is our most advanced R&D initiative. Based on Nb3Sn conductor, this
magnet provides a maximum design field of 12 T of accelerator quality in a 43.5-mm
diameter bore. A 1 m long model of this magnet is now under construction (Fig.1a).
Several practice coils and mechanical models (Fig.1b) have been fabricated and tested to
verify the fabrication technology and magnet mechanical parameters. High temperature
insulation (ceramic and S2-glass) with ceramic binder has been successfully tested
during coil fabrication. Cold tests of this model are planned in March 2001. Fabrication
of second and third models has been started in November 2000.
Conceptual designs (magnetic and mechanical) of double bore cos-theta dipoles with
cold and warm iron yoke approaches have been developed (Fig.2a and 2b). These
designs utilize the same coil blocks as the single bore magnet and were optimized with
respect to the maximum bore field of 11-12 T, field quality and minimum yoke/magnet
size. A comparison of the two approaches reveals that the cos-theta coil geometry and
warm iron yoke minimizes the coil and yoke cross-section as well as the final magnet
size and weight without degradation of magnet performance. Conceptual designs of a
“common coil” high field dipole, based on a single layer coil and wide Nb3Sn cable have
also been developed (Fig.2c). These designs provide a nominal field of 10-11 T with
accelerator quality field in a magnet bore of 40-50 mm. Simple single layer coils and the
possible use of “wind and react” techniques offer the potential for reduced fabrication
costs. The engineering design of a short model has been started; magnet fabrication is
planned for FY2001. An experimental study of “react and wind” techniques is underway
using flat racetrack coils.
The use of Nb3Sn conductor typically results in significant coil magnetization effects in
high field magnets due to large effective filament diameters. A simple passive correction
technique based on thin iron strips installed in the magnet bore or inside the magnet coil
has been developed in order to reduce this effect. This approach might lead to a
significant increase in the dynamic range of accelerator magnets and relax the
requirements on the effective filament size in Nb3Sn strands.
The low field magnet program concentrates on cost reduction using existing SC
materials in an extremely simple and lightweight “Transmission Line Magnet”
configuration (Fig. 3). This is a single-turn, warm-iron 2-in-1 superferric magnet built
around a superconducting transmission line.
In the past year the transmission line conductor development has been successfully
completed with the operation of a 100,000 A SC test loop (Fig. 4). Five candidate
conductors were successfully tested and a baseline design meeting all requirements was
chosen. Samples tested included conventional NbTi “Rutherford” cable-in-conduit
conductor, a Nb3Al conductor that operated above 11K, and the preferred option: a
novel “coaxial-braid-in-conduit” conductor suggested by our collaborators at KEK and
fabricated at a job shop in Florida.
The cryogenic system for this magnet consists of cryogenic piping with superconductor
swaged into the wall of the piping. This year has seen considerable development of
ultra-low heat leak supports and shields for the transmission line, which reduces
operating costs and allows smaller pipe sizes to deliver liquid He. If the projected low
heat leak of this design is confirmed in complete system tests, the specific cryogenic
power consumption of this design should be about 1/5th of the SSC or 1/10th of the LHC.
Optimization and test of the of the iron shape has arrived at a workable 2D profile which
provides adequate field quality above 1.9 T. This design is the basis for industrially
fabricated iron cores/cryopipe assemblies which have been ordered for the multi-magnet
system tests under construction in the M-west beam line at Fermilab. 100 kA power
supplies and current leads for this test are also under construction.
Fermilab’s Short Sample Test Facility, which includes a 17 T solenoid in 1.8-4.2 K LHe
dewar, two power supplies, control and DAQ systems, and a variable temperature insert
has been in operation for the last two years reaching testing rates of 40 samples per
month. It provides support for magnet R&D programs at Fermilab and contributes to the
national superconductor R&D program. A scanning electron microscope (SEM) is being
added to this facility in January 2001. We have purchased and studied several different
types of Nb3Sn strands with diameters from 0.3 to 1.0 mm. Strands were produced using
“Internal Tin” (IT), Modified Jelly Roll” (MJR), and “Powder in Tube” (PIT) methods.
Strand characterization includes measurements of Ic(B)/Jc(B), n-value, RRR, M(B), deff,
SEM studies and chemical analysis. Heat treatment optimization studies indicate a
possible reduction of reaction time for MJR and IT strands by factor of 2.
Rutherford-type cables made of different Nb3Sn strands have been studied. The studies
included effects of cable design and geometry, Ic degradation during cabling, and cable
bending (for reacted cables) and compression. An experimental cabling machine with up
to 28-strand capacity has been purchased and now is being installed at Fermilab. This
facility will allow further advances in our cable studies.
Publications:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
G. Ambrosio et al., “Conceptual Design of the Fermilab Nb3Sn High Field Dipole
Model”, in proceedings of 1999 Particle Accelerator Conference, New York, March
1999, pp. 174-176.
D.R. Chichili et al., “Niobium-Tin Magnet Technology Development at Fermilab“, in
proceedings of 1999 Particle Accelerator Conference, New York, March 1999.
G.W. Foster et al., “Measurements of a Crenelated Iron Pole Tip for the VLHC
Transmission Line Magnet”, in proceedings of 1999 Particle Accelerator Conference,
New York, March 1999, pp. 3327-3329.
E. Barzi et al., “Study of Strand Critical Current Degradation in a Rutherford Type
Nb3Sn Cable”, in proceedings of CEC’99, Montreal (Canada), July 1999.
G. Ambrosio et al., “Conceptual Design Study of High Field Magnets for Very Large
Hadron Collider”, IEEE Transactions on Applied Superconductivity, 10(1):310, 2000.
G. Ambrosio et al., “Conceptual Design of a Common Coil Dipole for VLHC”, IEEE
Transactions on Applied Superconductivity, 10(1): 330, 2000.
G. Ambrosio et al., “Development of the 11 T Nb3Sn Dipole Model at Fermilab”,
IEEE Transactions on Applied Superconductivity, 10(1): 298, 2000.
G. Ambrosio et al., “Magnetic Design of the Fermilab 11 T Nb3Sn Short Dipole
Model”, IEEE Transactions on Applied Superconductivity, 10(1): 322, 2000.
G. Ambrosio at al., “Mechanical Design and Analysis of the Fermilab 11 T Nb3Sn
Dipole Model”, IEEE Transactions on Applied Superconductivity, 10(1): 306, 2000.
G. Ambrosio et al., “Study of the React and Wind Technique for a Nb3Sn Common
Coil Dipole”, IEEE Transactions on Applied Superconductivity, 10(1): 338, 2000.
N. Andreev et al., “Fabrication and Testing of High Field Dipole Mechanical Model”,
IEEE Transactions on Applied Superconductivity, 10(1): 314, 2000.
G.W. Foster, V.S. Kashikhin, I. Novitski, “Design of a 2 Tesla Transmission Line
Magnet for the VLHC”, IEEE Transactions on Applied Superconductivity, 10(1): 202,
2000.
E. Barzi et al., “Heat Treatment Study of Nb3Sn Strands for the Fermilab’s High
Field Dipole Model”, IEEE Transactions on Applied Superconductivity, 10(1):1000,
2000.
D. R. Chichili et al., “Investigation of Cable Insulation and Thermo-Mechanical
Properties of Epoxy Impregnated Nb3Sn Composite”, IEEE Transactions on Applied
Superconductivity, 10 (1): 1317, 2000.
D.R. Chichili et al., “Fabrication of the Shell-Type Nb3Sn Dipole Model at Fermilab”,
ASC’2000, Virginia Beach, VG, September 2000.
V.V. Kashikhin and A.V. Zlobin, “Magnetic Designs of 2-in-1 Nb3Sn Dipole Magnets
for VLHC”, ASC’2000, Virginia Beach, VG, September 2000.
V.V. Kashikhin and A.V. Zlobin, “Correction of the Persistent Current Effect in Nb3Sn
Dipole Magnets”, ASC’2000, Virginia Beach, VG, September 2000.
18. D.R. Chichili et al., “Mechanical Design and Analysis of Fermilab 2-in-1 Shell-Type
Nb3Sn Dipole Models”, ASC’2000, Virginia Beach, VG, September 2000.
19. I. Novitski et al., “Design and Mechanical Analysis of a Single-Layer Common Coil
Dipole for VLHC”, ASC’2000, Virginia Beach, VG, September 2000.
20. G. Ambrosio et al., “Development of React & Wind Common Coil Dipoles for VLHC”,
21. S. Yadav et al., “Coil Design Issues for the High Field Dipole at Fermilab”,
22. P. Bauer et al., “Fabrication and Testing of Rutherford-Type Cables for React and
Wind Accelerator Magnets”, ASC’2000, Virginia Beach, VG, September 2000.
23. E. Barzi et al., “Study of Nb3Sn Strands for Fermilab’s High Field Dipole Models”,
24. E. Barzi et al., “Strand Critical Current Degradation in Nb3Sn Rutherford Cables”,
25. E. Barzi et al., “Heat treatment optimization of internal tin Nb3Sn strands”,
26. J. McDonald and E. Barzi, “A Model for Jc in Granular A-15 Superconductors”,
Current Staff:
•
•
•
•
•
•
•
•
•
•
Limon P. – PI
Foster B. – Co-PI, Low Field
Zlobin A. – Co-PI, High Field
Yamada R.– Scientist
Ambrosio G. – Scientist
Bauer P. – Postdoc
Andreev N. – Senior Engineer
Kashikhin V. - Senior Engineer
Piekarz H. – Senior Engineer
Terechkine I. – Senior Engineer
•
•
•
•
•
•
•
•
•
•
Barzi E. – Engineer
Chichili D. – Engineer
Huang Y. – Engineer
Novitski I. – Engineer
Yadav S. – Engineer
Kim S.-W. – Guest Engineer
Rey J.-M. – Guest Engineer
Kashikhin V.V. – Ph.D. Student
Fratini M. – Graduate Student
Imbasciati L. – Graduate Student
P.J. Limon, G.W. Foster and A.V. Zlobin
Fermilab MS-316
P.O. Box 500
Batavia IL 60510
PHONE:
FAX:
E-MAIL:
Website:
630/840-3411
630/840-3756
[email protected], [email protected], [email protected]
http://vlhc.org/
Figure 1: Cos-theta short dipole model (a) and its instrumented mechanical model (b).
Figure 2: Magnetic designs of double-bore cos-theta dipoles with cold (a) and warm (b)
iron yoke, and single-layer common coil dipole (c).
c)
240.0
Component: |B|
BMOD
0.0574443
2.514357
20 cm.
2-in-1 Warm-Iron
“Double-C” Magnet
Flux Return
Extruded Aluminum
Beam Pipes with side
pumping chamber
LHe
75 kA Superconducting
Transmission Line
Alternating-Gradient
Pole Tips (no Quadrupoles)
structure is continuous
in long lengths
KEY FEATURES:
Simple Cryogenic System
Small Superconductor Usage
Small Cold Mass
Low Heat Leak
Continuous in Long Lengths
No Quads or Spool Pieces
Warm Bore Vacuum System
Standard Construction Methods
0.061
Component: |B|
BMOD
0.113741
4.971269
Figure 3: Low field magnet cross-section.
•
•
•
•
•
•
•
•
0.002
200.0
0.042
160.0
b)
Helium
Return
Line
Supply
Line
Structural Support Tube/
CryoLineVacuum Jacket
Cryopipes for RingWide Distribution of
Single-Phase Helium
Current Return
0.04
40.0
40.0
40.0
a)
1.987968
160.0
160.0
200.0
200.0
240.0
240.0
3.862194
Figure 4: Transmission line test facility.
Generic R&D for HEP Accelerators
J. Corlett – Lawrence Berkeley National Laboratory
Summary:
Computational design of higher-order-mode damped RF cavities
High-intensity and low-emittance storage rings typically required in high-energy physics
experiments require accelerating radiofrequency systems with damped higher-order-mode
(HOM) impedances. An impedance reduction of two to three orders of magnitude is
required to avoid causing instabilities in the charged-particle beams, or to produce a regime
where fast feedback systems may control residual oscillations of the beam. While damping
the HOM’s, it is important not to severely degrade the performance of the accelerating
mode of the cavity, which provides energy to the particle beams.
The figure on the next page shows a time-domain computation of the dipole mode
fields in a cavity, over different timescales, which may be excited by the beam passing
through the cavity. The power generated in these modes may propagate into specially
designed and located damping waveguides, where it is dissipated and the fields can be
seen to decay. A Fourier transform of this information
allows modal properties to be determined. Using stateof-the-art computational facilities allows these results to
be produced within hours, and cavity design for optimal
higher-order-mode damping becomes much more
efficient than in the past (when many frequency
domain computations of similar CPU time were
required).
A 3-D model of a cavity with damping waveguide
cavities is shown at left; the damping waveguides are
bent such that the waveguide cross-section is in one of
the Cartesian planes of the model. This allows the use
of waveguide boundary conditions to model power flow
into the waveguides without reflection.
The time-domain technique allows rapid optimization of
the position and cross-section of the damping
waveguides to minimize HOM impedances, with minimal
perturbation to the accelerating mode.
Publications:
1. J. Corlett, "NLC Damping Rings RF Cavities", Proceedings of the VIII International
Workshop on Linear Colliders, INFN-LNF, Frascati (Rome) Italy, 21-26 October 1999
http://wwwsis.lnf.infn.it/talkshow/lc99/Corlett1a/talk.pdf
2. J. Corlett, "NCL Damping Rings Wiggler Straights", Proceedings of the VIII International
Workshop on Linear Colliders, INFN-LNF, Frascati (Rome) Italy, 21-26 October 1999
http://wwwsis.lnf.infn.it/talkshow/lc99/Corlett1b/talk.pdf
3. J. Corlett and C. Ng, "NCL Damping Rings Broadband Longitudinal Impedance",
Proceedings of the VIII International Workshop on Linear Colliders, INFN-LNF, Frascati
(Rome) Italy, 21-26 October 1999
http://wwwsis.lnf.infn.it/talkshow/lc99/Corlett1c/talk.pdf
4. T. Okugi, T. Hirose, H. Hayano, S. Kamada, K. Kubo, T. Naito, K. Oide, K. Takata, Seishi
Takeda, N. Terunuma, N. Toge, J. Urakawa, S. Kashiwagi, M. Takano, D. McCormick, M.
Minty, M. Ross, M. Woodley, F. Zimmermann, J. Corlett, “Evaluation of extremely small
horizontal emittance,” Phys. Rev. ST Accel. Beams 2, 022801 (1999)
5. J.Urakawa et al, “Recent Results on KEK/ATF Damping Ring” Contributed to the XVIIth
International Conference on High Energy Accelerators, September 7-12, 1998, Dubna,
LBNL-42333
6. M. Sullivan, Y. Cai, M. Donald, S. Ecklund, T. Fieguth, C. Field, A.S. Fisher, L.
Henderson, T. Himel, P. Krejcik, G. Mazaheri, M. Minty, I. Reichel, J. Seeman, U.
Wienands, J. Corlett, M. Zisman, W. Kozanecki, M. Placidi, A. Hofmann, "Beam Beam
Collisions at the PEP-II B Factory," PAC’99, New York, March 29-April 2, 1999.
7. J.N. Corlett, R.A. Rimmer, P. Corredura, T. O. Raubenheimer, M.C. Ross, H. Schwarz,
R.C. Tighe, M. Minty, M. Franks, “The Next Linear Collider Damping Ring RF System”,
PAC’99, New York, March 29-April 2, 1999.
8. T. Raubenheimer et al, “The Next Linear Collider Damping Ring Complex”, PAC’99, New
York, March 29-April 2, 1999.
9. J. Corlett, M. Green, H. Kirk, D. Li, A. Moretti, R. Palmer, D. Summers, Y. Zhao, and N.
Holtkamp, “RF Accelerating Structures for the Muon Cooling Experiment”, PAC’99, New
York, March 29-April 2, 1999.
10. W. Barry, J. Byrd, J. Corlett, D. Li, J. Fox, M. Minty, S. Prabhaker, D. T Eytelman,
“Operational Experience with the PEP-II Transverse Coupled-Bunch Feedback Systems,”
PAC’99, New York, March 29-April 2, 1999.
11. P.R. Cameron, A.U. Luccio, W.W. MacKay and T.J. Shea, M. Conte and R.Parodi, S.
Kaplan, W.C. Barry, J.N. Corlett, D.A. Goldberg and R.A. Rimmer, K. Jacobs and T.
Zwart, “Apparatus and Motivation for the Measurement of the Relativistic Longitudinal
Magnetic Moment,” PAC’99, New York, March 29-April 2, 1999.
12. J. Corlett, Derun Li, N. Holtkamp, A. Moretti, H. Kirk, “A High Power RF Coupler Design
for Muon Cooling RF Cavities,” PAC’99, New York, March 29-April 2, 1999.
13. H.-U. Wienands for the PEP-II Commissioning Team, “Beam Commissioning of the PEPII High Energy Ring,” PAC’99, New York, March 29-April 2, 1999.
14. D. Li, W. Turner, and J. Corlett, “Temperature Distributions on Beryllium Windows in
µ+µ- Cooling RF Cavity”, 4th International Conference on Physics Potential &
Development of µ+µ- Colliders, San Francisco, CA (December 1997)
15. W. Barry, J. N. Corlett, D. Li, D. and A. Goldberg “Design of a Schottky-Signal Detector
for Use at the RHIC Collider,” EPAC’98, Stockholm, Sweden (June 1998)
16. A. Moretti, J. Corlett, D. Li, W. Turner, H. Kirk, R. Palmer, and Z. Zhao, “RF System
Concepts for a Muon Cooling Experiment,” EPAC’98, Stockholm, Sweden (June 1998)
17. W. Barry, J. N. Corlett, G. Lambertson, D. Li, J. Fox, D. Teytelman, “Initial
Commissioning Results from the PEP-II Transverse Coupled-Bunch Feedback Systems,”
EPAC’98, Stockholm, Sweden (June 1998)
18. D. Li, J. Corlett, and A. Mitra, “A 35 MHz Rebuncher Cavity for ISAC at TRIUMF,”
EPAC’98, Stockholm, Sweden (June 1998)
Current Staff:
•
•
•
•
•
John Corlett
Robert Rimmer
Derun Li
Stefano De Santis
David Lozano
PI
Dr. John Corlett
Lawrence Berkeley National Laboratory
1 Cyclotron Road MS 71-259
Berkeley, CA 94720
PHONE:
FAX:
E-MAIL:
(510) 486-5228
(510) 486-7981
[email protected]
Summary:
Optical-Accelerator Experiments at Berkeley Lab
Wim Leemans, Berkeley Lab Center for Beam Physics
The l’OASIS Group (Laser Optics and Accelerator Systems Integrated Studies) of Berkeley
Lab’s Center for Beam Physics performs experimental and theoretical studies of the
interaction of high intensity lasers with particle beams and plasmas. It emphasizes
development of compact, high-gradient, laser-driven particle accelerators. The
18
experimental program consists of three parts: guiding of high intensity laser beams (10
2
W/cm ) over macroscopic distances (1- 10 cm scale length) in a plasma channel; probing
of plasma wakefields excited in the channels by the laser pulse using optical techniques;
and study of laser-triggered injection of electrons into a plasma structure. The theoretical
program develops analytical and computational tools to predict and analyze the physics
involved in the interaction of high intensity laser pulses with beams and plasmas.
A particular highlight of recent work has been the production of high repetition rate (5-10
Hz) relativistic electron beams from plasmas by means of laser wakefield acceleration. By
focusing a high-power laser beam onto a high-pressure helium gasjet, electron beams
containing multiple nanocoulombs of charge were generated and accelerated to energies
up to tens of MeV over mm-scale distances. Spatially well-collimated beams were
measured. The high energy and repetition rate allowed use of the electron beams to
produce radioisotopes in Pb and Cu targets. On-line -ray and neutron monitoring was
implemented to aid in the tuning of the accelerator.
The energy spread, however, was 100%. To reduce the energy spread, we are
implementing the “colliding pulse” optical injection method, originally proposed by Esarey
et al. (Phys. Rev. Lett. 1997). As of this writing (November 2000), implementation of the
colliding-pulse laser injection method is underway. This method is expected to produce
low emittance (1 π mm-mrad), low energy spread (1%), 40 MeV femtosecond electron
bunches containing 107 electrons per bunch. By combining this injector with plasma
channels on the order of 3 cm, we expect to produce a 1 GeV compact, laser driven
accelerator module using our 10 TW laser system. Future upgrade of the laser system to
the 100 TW class is expected to allow us to develop a 10-cm-long, 10 GeV module. We are
also exploring the use of this unique “tabletop” source of femtosecond/attosecond electron
bunches. Applications could include a self-amplified stimulated emission free-electron
laser, a high brightness source for infrared and THz radiation, and perhaps medical isotope
production.
The theory and computational efforts of the Group aim at development of new concepts
and analysis of ongoing experiments at the l’OASIS Laboratory. Significant progress has
been made in providing analytic and computational tools to predict and analyze the
experimental results. New results on laser propagation in plasma channels have been
obtained by extending the conventional paraxial propagation model through the inclusion
of non-paraxial terms. The new model allows for fast and accurate modeling of the selfmodulated and Raman forward scattering laser instabilities, which are relevant to the
experiment. A novel two-dimensional fluid code is under development, allowing laser and
plasma evolution to be calculated self-consistently, under the assumption that no particle
trapping occurs. To further extend our capabilities, a collaborative effort between UC
Berkeley, University of Colorado, and our group has been implemented on the use of
particle-in-cell (PIC) codes for self-consistent modeling of the laser-plasma interactions,
including particle trapping and acceleration.
Publications:
Refereed papers
1. C. B. Schroeder, E. Esarey, P. B. Lee, W. P. Leemans, and J. S. Wurtele, “Generation of
ultrashort electron bunches by colliding laser pulses,” Phys. Rev. E 59, 6037-6047
(1999).
2. E. Esarey and W. P. Leemans, “Non-paraxial propagation of ultrashort laser pulses in
plasma channels,” Phys. Rev. E 59, 1082-1095 (1999).
3. R. Govil, W. P. Leemans, E. Yu Backhaus and J. S. Wurtele, “Observation of return
current effects in a passive plasma lens,” Phys. Rev. Lett. 83, 16 (1999).
4. P. Volfbeyn, E. Esarey, and W.P. Leemans, “Guiding of laser pulses in plasma channels
created by the ignitor-heater technique,” Phys. Plasmas 6, 2269-2277 (1999).
5. E. Esarey, C.B. Schroeder, W.P. Leemans, and B. Hafizi, “laser-induced electron
trapping in plasma-based accelerators,” Phys. Plasmas 6, 2262-2268 (1999).
6. P. Catravas, W. P. Leemans, J. S. Wurtele, M. Zolotorev, M. Babzien, I. Ben-Zvi, Z.
Segalov, X.-J. Wang, and V. Yakimenko, “Measurement of electron-beam bunch length
and emittance using shot-noise-driven fluctuations in incoherent radiation,” Phys. Rev.
Lett. 82, 26 (1999).
7. A.H. Chin, R. W. Schoenlein, T. E. Glover, P. Balling, W. P. Leemans, and C. V. Shank,
“Ultrafast structural dynamics in InSb probed by time-resolved x-ray diffraction,” Phys.
Rev. Lett. 83, 2 (1999).
8. D. Bernard, F. Amiranoff, W.P. Leemans, E. Esarey, and C. Joshi, “Alternative
interpretation of Nucl. Instr. and Meth. in Phys. Res. A 410 (1998) 357 (H. Dewa et
al.),” Nucl. Instrum. Meth. A 432, 277-231 (1999).
9. E. Esarey, C. B. Schroeder, B. A. Shadwick, J. S. Wurtele, and W. P. Leemans,
“Nonlinear theory of non-paraxial laser pulse propagation in plasma channels,” Phys.
Rev. Lett. 84, 3081 (2000).
10. M. J. Hogan, R. Assman, F.-J. Decker, R. Iverson, P. Raimondi, S. Rokni, R. H.
Siemann, D. Walz, D. Whittum, B. Blue, C. E. Clayton. E. Dodd, R. Hemker, C. Joshi, K.
A. Marsh, W. B. Mori, S. Wang, T. Katsouleas, S. Lee, P. Muggli, P. Catravas, S.
Chattopadhyay, E. Esarey, and W. P. Leemans, “E-157: a 1.4-m-long plasma wake
field acceleration experiment using a 30 GeV electron from the Stanford Linear
Accelerator Center linac,” Phys. Plasmas 7, 2241-2248 (2000).
11. W. P. Leemans, S. Chattopadhyay, E. Esarey, A. Zholents, M. Zolotorev, A. H. Chin, R.
W. Schoenlein, and C. V. Shank, “Femtosecond x-ray generation through relativistic
electron beam-laser interaction,” Comptes rendus de l'Académie des Sciences (C.R.
Acad. Sci. Paris) Serie IV, Tome 1, 3, pp. 279-296 (2000).
12. S. Y. Chen,A. Maksimchuk, E. Esarey, and D. Umstadter, “Observation of phasematched relativistic harmonic generation,” Phys. Rev. Lett. 84, N24, 5528-5531
(2000).
13. P. E. Catravas, S. Chattopadhyay, E. Esarey, W. P. Leemans, R. Assmann, F.-J. Decker,
M. J. Hogan, R. Iverson, R. H. Siemann, D. Walz, D. Whittum, B. Blue, C. Clayton, C.
Joshi, K. A. Marsh, W. B. Mori, S. Wang, T. Katsouleas, S. Lee, and P. Muggli,
“Measurements of radiation near an atomic spectral line from the interaction of a 30
GeV electron beam and a plasma,” submitted to Phys. Rev. Lett. (November 2000).
14. W. P. Leemans, D. Rodgers, P. E. Catravas, C. G. R. Geddes, G. Fubiani, E. Esarey, B.
A. Shadwick, R. Donahue, and A. Smith, “Gamma-neutron activation experiments using
laser wakefield accelerators,” submitted to Phys. Plasmas (November 2000).
15. E. Esarey, “Laser cooling of electron beams via Thomson scattering,” Nucl. Instrum.
Meth. A (in press).
16. T. Katsouleas, W. B. Mori, E. Dodd, S. Lee, R. Hemker, C. Clayton, C. Joshi, and E.
Esarey, “Laser steering of particle beams: refraction and reflection of particle beams,”
Nucl. Instrum. Meth. A (in press).
Conference Proceedings
1. W. P. Leemans, L. Archambault, P. Catravas, S. Chattopadhyay, S. DiMaggio, E.
Esarey, K.-Z. Guo, C. B. Schroeder, B. A. Shadwick, P. Volfbeyn and J. S. Wurtele,
“Ultrashort electron bunches and laser channeled wakefield acceleration,” in
Proceedings of the 1999 Particle Accelerator Conference, New York, NY (Institute of
Electrical and Electronics Engineers (IEEE ) catalog no. CH36366 (1999).
2. E. Esarey and W. P. Leemans, “Scaling laws for laser wakefield accelerators,” in
3. P. Volfbeyn and W. P. Leemans, “Laser wakefield diagnostic using holographic
longitudinal interferometry,” in Proceedings of the 1999 Particle Accelerator
Conference, New York, NY (Institute of Electrical and Electronics Engineers (IEEE )
catalog no. CH36366 (1999).
4. S. DiMaggio, L. Archambault, P. Catravas, P. Volfbeyn, W. Leemans, K. March, P.
Muggli, S. Wang, and C. Joshi, “Development of one meter-long lithium plasma source
and excimer mode reduction for plasma wakefield,” in Proceedings of the 1999
Particle Accelerator Conference, New York, NY (Institute of Electrical and Electronics
Engineers (IEEE ) catalog no. CH36366 (1999).
5. P. Catravas, W. P. Leemans, E. Esarey, M. Zolotorev, D. Whittum, R. Iverson, M.
Hogan, and D. Walz, “Beam profile measurement at 30 GeV using optical transition
radiation,” in Proceedings of the 1999 Particle Accelerator Conference, New York, NY
(Institute of Electrical and Electronics Engineers (IEEE ) catalog no. CH36366 (1999).
6. R. Assman, P. Chen, F.J. Decker, R. Iverson, M. J. Hogan, S. Rokni, R. H. Siemann, D.
Walz, D. Whittum, P. Catravas, S. Chattopadhyay, E. Esarey, W. P. Leemans, P.
Volfbeyn, C. Clayton, R. Hemker, C. Joshi, K. Marsh, W. B. Mori, S. Wang, T.
Katsouleas, S. Lee, and P. Muggli, “Progress toward E-157: a 1 GeV plasma wakefield
accelerator radiation,” in Proceedings of the 1999 Particle Accelerator Conference, New
York, NY (Institute of Electrical and Electronics Engineers (IEEE ) catalog no. CH36366
(1999).
7. E. Esarey, C. B. Shroeder, B. A. Shadwick, W. P. Leemans, and J. Wurtele, “Nonparaxial propagation of ultrashort laser pulses in underdense plasma radiation,” in
8. W. Leemans, “Working group VI summary report,” in Proceedings of the International
Committee for Future Accelerators 17th Advanced Beam Dynamics Workshop on
Future Light Sources, Argonne, IL, http://www.aps.anl.gov/conferences/FLSworkshop/
(1999).
9. E. Esarey and W. P. Leemans, “Femtosecond Electron and X-Ray Generation by Laser
and Plasma-Based Sources,” in Proceedings of the International Committee for Future
Accelerators Workshop on the Physics of High Brightness Beams (World Scientific,
Singapore, in press); also published as
http://stout.physics.ucla.edu/papers/index.html#ICFA99.
10. W. P. Leemans, P. E. Catravas, E. Esarey, G. Fubiani, M. Pilloff, B. A. Shadwick, J. van
Tilborg, J. S. Wurtele, and S. Chattopadhyay, “All-optical plasma based acceleration,”
in Proceedings of the 20th International Linac Conference, Monterey, CA (Phys. Rev.
Special Topics: Accelerators and Beams, special edition, in press, http://prstab.aps.org/speced/Linac2000).
11. W.P. Leemans, “Ultra-short electron bunch and x-ray generation using high power
lasers,” in Proceedings of the Ultraintense Laser Interactions and Applications (ULIA)
Conference, Pisa, Italy (Laser and Particle Beams, in press).
12. E. Esarey, “Non-paraxial theory of ultrashort laser pulser propagation in underdense
plasmas,” abstract submitted to the 42nd Annual Meeting of the American Physical
Society Division of Plasma Physics, Quebec City, Canada, 2000
(http://positron.aps.org/meet/DPP00/baps/index.html).
13. B. Shadwick, E. Esarey, W. P. Leemans, and G. M. Tarkenton, “Fluid modeling of selfmodulated laser wakefield experiments,” abstract submitted to the 42nd Annual
Meeting of the American Physical Society Division of Plasma Physics, Quebec City,
Canada, 2000, (http://positron.aps.org/meet/DPP00/baps/index.html).
14. B. Shadwick, W. A. Buell, and J. C. Bowman, “Structure preserving integration
algorithms,” in Proceedings of the 2nd International Workshop on Scientific Computing
and Applications, Kananaskis Village, Alberta, Canada (Nova Science Publishers,
Huntington, New York, in press).
15. W.P. Leemans, D. Rodgers, P. E. Catravas, G. Fubiani, C. G. R. Geddes, E. Esarey, B.
A. Shadwick, J. van Tilborg, S. Chattopadhyay, J.S. Wurtele, L. Archambault, M.R.
Dickinson, S. DiMaggio, R. Short, K. L. Barat, R. Donahue, J. Floyd, A. Smith, and E.
Wong, “All optical accelerator experiments at LBNL,” in Proceedings of the 20th
International Linac Conference, Monterey, CA (Phys. Rev. Special Topics: Accelerators
and Beams, special edition, in press, http://prst-ab.aps.org/speced/Linac2000).
16. W. P. Leemans, D. Rodgers, P.E. Catravas, G. Fubiani, C. G. R. Geddes, E. Esarey, B.
A. Shadwick, G. J. H. Brussaard, J. van Tilborg, S. Chattopadhay, J. S. Wurtele, L.
Archambault, M. R. Dickinson, S. DiMaggio, R. Short, K. L. Barat, R. Donahue, J. Floyd,
A. Smith, and E. Wong, “Laser wakefield accelerator experiments at LBNL,” in
Proceedings of the 9th Workshop on Advanced Accelerator Concepts, Santa Fe, NM,
2000, edited by P. Colestock (American Institute of Physics, in press).
17. D.L. Bruhwiler, R. Giacone, J.R. Cary, J.P. Verboncoeur, P. Mardahl, E. Esarey, and W.
Leemans, “Modeling beam-driven and laser-driven plasma wakefield accelerators with
XOOPIC,” in Proceedings of the 9th Workshop on Advanced Accelerator Concepts, Santa
Fe, NM, 2000, edited by P. Colestock (American Institute of Physics, in press).
18. G. Fubiani., W. Leemans, and E. Esarey, “Studies of Space-Charge Effects in Ultrashort
Electron Bunches,” in Proceedings of the 9th Workshop on Advanced Accelerator
Concepts, Santa Fe, NM, 2000, edited by P. Colestock (American Institute of Physics,
in press).
19. E. Esarey, B. A. Shadwick, C. B. Schroeder, J. S. Wurtele, and W. P. Leemans,
“Nonparaxial propagaton of intense laser pulses in plasmas,” in Proceedings of the 9th
Workshop on Advanced Accelerator Concepts, Santa Fe, NM, 2000, edited by P.
Colestock (American Institute of Physics, in press).
20. B. A. Shadwick, G. M. Tarkenton, E. H. Esarey, and W. P. Leemans, “Fluid modeling of
intense laser-plasma interactions,” in Proceedings of the 9th Workshop on Advanced
Accelerator Concepts (Santa Fe, NM, 2000), edited by P. Colestock (American Institute
of Physics, in press).
21. E. Esarey., P. Catravas, and W.P. Leemans, “Betatron radiation from electron beams in
plasma focusing channels,” in Proceedings of the 9th Workshop on Advanced
Accelerator Concepts, Santa Fe, NM, 2000, edited by P. Colestock (American Institute
of Physics, in press).
Ph.D. Dissertation
1. C. B. Schroeder, “Plasma-based accelerating structures,” Ph. D. thesis, University of
California, Berkeley, 1999; also available as Lawrence Berkeley National Laboratory
report LBNL-44779.
Current Staff:
Leemans, W.P.
Esarey. E.
Catravas, P.
Shadwick, B.A.
Toth, C.
Geddes, C
Fubiani, G
Staff Scientist
Scientist
Scientist
Staff Scientist
Graduate Student
Graduate Student
Wim P. Leemans (PI)
Ernest Orlando Lawrence Berkeley National Laboratory
1 Cyclotron Road, MS 71-259
Berkeley, California 94720
PHONE: 510/486-7788
FAX: 510/486-7981
WEBSITE: http://bc1.lbl.gov/CBP_pages/EBP/ebp.html
Figure 1: Lay-out of experiment showing the laser beam exiting the compressor, being reflected by mirror M1
onto the off-axis parabola (OAP), which focuses it onto the gas-jet. The resulting electron beam is measured
using the integrated current transformer (ICT) and is dispersed in the magnetic spectrometer onto a
phosphor screen. The screen is imaged with the CCD. Plasma densities are measured with the interferometer
(INT) and the laser beam is analyzed using the single-shot autocorrelator (SSA), the frequency resolved
optical gating system (FROG) and an imaging optical spectrometer (Spec.).
3.5
3
Gasjet profile (half)
ne (x1019/cm3)
2.5
2
1.5
1
0.5
0
-2500
a
-2000
-1500
-1000
z distance fromgasjet axis (µm)
b
-500
0
c
o
10
Electron Beam Images
Figure 2: Electron beam profile recorded on a phosphor screen for different focal positions of the laser
beam on the gasjet. The top image shows half of the gasjet profile measured using side-on
interferometry. As can be seen in profile (b), an electron beam with narrow (about 1˚) opening angle
can be produced by focusing on the edge of the jet.
LBNL Superconducting Magnet Development Progrm
S.A. Gourlay and A. Jackson – Lawrence Berkeley National Laboratory
Summary:
Description:
Our superconducting magnet program is primarily directed towards development of
high field magnets for future accelerators. At present, accelerator magnet technology is
dominated by the use of NbTi superconductor. To achieve fields above 10 Tesla
requires the use of A15 compounds, the most practical and available of which is Nb3Sn.
In a practical geometry, magnets based on Nb3Sn technology should be able to exceed
fields of 14 -15 Tesla at 4.2 K. The challenge lies in incorporating the intrinsically brittle,
strain sensitive material, into a realistic magnet where it is subjected to stresses
approaching 150 MPa. Advances in fabrication techniques and materials have allowed
us to reinvestigate the advantages of simple racetrack coil geometries lending
advantages in support structure design and fabrication. Following the successful
construction and test of a 6 Tesla racetrack magnet (RD-2) in the Fall of 1998, the
group has been focusing on the design and fabrication of a 14 Tesla magnet (RD-3),
which would push the limits of current technology. The design consists of one inner and
two outer coil modules.
The outer coil modules were tested separately, early this year, in a configuration
designated RT-1, and achieved a field of 12.2 Tesla (12.36 Tesla peak field on the
winding), more than twice that of RD-2. This was made possible due to the availability of
state-of-the-art superconductor with a non-Cu current density of over 2,000 A/mm2. This
represents a factor of three increase compared to the conductor used for RD-2. The
construction of magnets at higher fields requires careful consideration of mechanical
support structure issues. In fact, aside from the conductor, the support structure is the
most important factor in developing a robust and cost effective high field magnet.
Relative to the 6 Tesla magnet (RD-2) the 14 Tesla magnet will have forces 5 times
higher. The integrated horizontal Lorentz forces total about 9 MN (1,000 tons), acting to
push the windings apart. The success of the interim test using the outer coil modules
prompted development of a coil support design that makes use of inflatable bladders
which are used as a temporary internal "press” to load the coil modules inside an
aluminum shell, using a support structure geometry similar to that of RT-1.
The inner coil module was combined with the two outer coil modules using the new
support scheme and the final assembly of RD-3 was completed in August. Testing
commenced in early September, but during the first ramp an insulation failure occurred,
which resulted in arc damage to two modules. The damaged coils are now being rebuilt
and we anticipate re-testing the magnet within the next few months.
Publications:
1.
2.
3.
4.
5.
6.
7.
Dietderich, D.R., "Critical Current Variation of Rutherford Cable of Bi-2212 in
High Magnetic Fields with Transverse Stress,” presented at the Materials and
Mechanisms of Superconductivity, High Temperature Superconductors, Houston,
TX, Feb. 20-25, 2000. To be published in Physics C, LBNL-45073, SC-MAG-699.
Gourlay, S., Chow, K., Dietderich, D.R., Gupta, R., Harnden, W., Lietzke, A.F.,
McInturff, A.D., Millos, G.A., Morrison, L., Morrison, M., Scanlan, R.M.,
"Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole
Magnet, 1999 Particle Accelerator Conference, New York, NY, 29 March to 2
April, LBNL-42831, SC-MAG-715.
Scanlan, R.M.,"Nb3Sn Conductor Devleopment for HEP--Plans and Status for the
Conductor Development Group,” Applied Superconductivity Conference, Virgina
Beach, VA, September 17-22, 2000, LBNL-45051, SC-MAG-698.
Benjegerdes, B., Bish, P., Byford, D., Caspi, S., Chow, K., Dietderich, D., Gourlay,
S., Gupta, R., Hafalia, R., Hannaford, R., Harnden, W., Higley, H., Jackson,A.,
"Fabrication and Test of Nb3Sn Racetrack Coils at High Field,” Applied
Superconductivity Conference, Virgina Beach, VA, September 17-22, 2000, LBNL45138, SC-MAG-701.
Gourlay, S., Caspi, S., Hafalia, R., Sabbi, G., "Mechanical and Magnetic Design of
Field Shaping Coils for Racetrack Dipole Magnets,” Applied Superconductivity
Conference, Virgina Beach, VA, September 17-22, 2000, LBNL-45139, SC-MAG702.
Dietderich, D.R., Scanlan, R.M., "Critical Current Variation as a Function of
Transverse Stress of Bi-2212 and Nb3Sn Rutherford Cable,” Applied
Superconductivity Conference, Virgina Beach, VA, September 17-22, 2000, LBNL45179, SC-MAG-705.
Caspi, S., "The Use of Pressurized Bladders for Stress Control of Superconducting
Magnets,” Applied Superconductivity Conference, Virgina Beach, VA, September
17-22, 2000, LBNL-45180, SC-MAG-706.
Invited Talks 2000 Only:
1.
2.
3.
4.
5.
D.R. Dietderich, “Strain-Jc Measurements in Cables, Low Temperature
Superconductor Workshop, Santa Rosa, CA.
D.R. Dietderich, “Effects of Heat Treatment on Jc, RRR, and Stress Relief,” Low
Temperature Superconductor Workshop, Santa Rosa, CA.
S.A. Gourlay, “Common Coil Magnet R&D,” VLHC 2000 Annual Meeting, Port
Jefferson, NY.
S.A Gourlay, “Conductor and Insulation Issues in RT-1, RD-3 and Future
Magnets,” Low Temperature Superconductor Workshop, Santa Rosa, CA.
R.M. Scanlan, “Superconducting Materials for the Next Generation Colliders,”
VLHC Magnet Technologies Workshop, Port Jefferson, NY.
6.
7.
8.
R.M. Scanlan, “Conductor Development for High Energy Physics – Plans and
Status, “Applied Superconductivity Conference, Virgina Beach, VA.
R.M. Scanlan, “HEP Conductor Development Program,” Low Temperature
R.M. Scanlan, “Cabling Issues for High Field Magnets,” Low Temperature
Current Staff:
Program Head:
Deputy:
Engineering Staff:
Mechanical Technicians:
Physicists:
Alan Jackson
Alfred McInturff – Steering Body Leader
•
•
Shlomo Caspi
Ray Hafalia
•
•
•
•
•
•
•
Paul Bish
Roy Hannaford - Lead
Hugh Higley
Nate Liggins
Jim O’Neill - Supervisor
Evan Palmerston
Jim Swanson
•
•
•
•
•
Dan Dietderich
Steve Gourlay – S.C. Magnet Development Leader
Alan Lietzke
GianLuca Sabbi
Ron Scanlan – S.C. Materials & Cable Development
Leader
•
•
Bob Benjegerdes
Doyle Byford
•
•
•
Richard Schafer
Bob Schermer
Clyde Taylor
•
•
Kelly Molnar
Ken Saito
Electronics:
Retirees:
Undergraduate Students:
Stephen A. Gourlay
One Cyclotron Rd., MS 46-161
Berkeley, CA 94720
Phone: 510-486-7156
Fax: 510-486-5310
[email protected]
http://supercon.lbl.gov
RT - 1
RD - 3
Advanced Research and Development Group B
Robert Siemann, Stanford Linear Accelerator Center
Summary:
The primary goal of the research is to push the envelope of the advanced accelerator
technology, which is crucial for the success of high energy physics. High gradient RF, Laser
driven and plasma based accelerator are explored. Much of the work the ARDB group is
doing is with other principal investigators
•
W-band (75-110 GHz) accelerators with Prof. Kroll at UCSD.
•
LEAP experiment with Prof. Byer at Stanford. (See Page 83.)
•
Plasma wake experiment (E157) with Prof. Joshi at USC. (See Page 107.)
•
Pulsed heating experiment
•
Photonic Band Gap Fiber Accelerator
http://www.slac.stanford.edu/grp/arb/research/Wband/
http://www.slac.stanford.edu/grp/arb/research/PBGFA
Current Staff:
Robert H. Siemann
David Fryberger
Jim Spencer
Eric Colby
Mark Hogan
Dennis Palmer
Chris Barnes
Ben Cowan
Caolionn O’Connor
Tomas Plettner
David P. Pritzkau
Marie Anaya
Staff
Staff
Panofsky Fellow
Research Associate
Research Associate
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Graduate Student
Work Study Student
Robert H. Siemann (PI)
Stanford Linear Accelerator Center
2575 Sand Hill Road
Menlo Park, CA 94025
PHONE: 650-926-3892
Caveat: Prof. Siemann would not provide a summary description of his group’s research. Because the
editors believe that research to be important and in order to present complete coverage of the HEP
Advanced Technology R&D program, the above submission was abstracted from Prof. Siemann’s WEB
page and any errors and omissions are the fault of the editors.. Please contact Prof. Siemann directly
for more complete information.
Graduate Student Data FY2001
Last Name
First Name
(MI)
Sonnad
Kiran
Lee
Jinhyung
Shchelkunov
Sergey
Lafate
Kurtrease
Furzier
Silvie
Hilton
David
Al-Harbi
N.
Cosineau
S.
Fung
K.M.
Guo
W.
Ranjbar
V.
Wang
S.
Zhang
Y.
Jin
Lihui
Kheawpum
Orathai
Fiske
David
Stasevich
Timothy
Castle
M.
Cui
Y.
Gouveia
E.
Harris
J.
Kim
Y.
Li
H.
Virgo
M.
Erdelyi
Bela
Hoefkens
Jens
Von Bergmann Jens
Brown
Winthrop
Korbly
Stephen
Smirnova
Evgenya
Sirigiri
Jagadishwar
Chen
Huang
Huang
Saleh
Shoyuan
Hongtao
Ying
Ned
Institute
Advisor
University of Colorado, Boulder
University of Colorado, Boulder
Columbia University
Florida A&M University
University of Indiana
University of Maryland, College Park
Massachusetts Institute of
Technology
Technology
Technology
Technology
John R. Cary
John R. Cary
T.C. Marshall
Ronald L. Williams
S.W. Van Sciver
S.W. Van Sciver
Shy Lee
Shy Lee
Shy Lee
Shy Lee
Shy Lee
Shy Lee
Shy Lee
Jack Shi
Jack Shi
Alex J. Dragt
Alex J. Dragt
Lawson
Martin Reiser
Victor Granastein
Martin Reiser
Victor Granastein
Martin Reiser
Martin Reiser
Martin Berz
Martin Berz
Martin Berz
Richard J. Temkin
Richard J. Temkin
Richard J. Temkin
Richard J. Temkin
Donald
Donald
Donald
Donald
Umstadter
Umstadter
Umstadter
Umstadter
Buta
Lee
Peng
Li
F.
E.
x.
Xiohu
Barnes
Cowan
Plettner
He
Cheshkov
Backhaus
Charman
Geddes
Kumar
He
Blue
Filip
Huang
Narang
Wang
Anderson
Andonian
Bishofburger
Ding
Musumeci
Murokh
Thompson
Vlaicu
Hoffman
Lee
Spence
Yoshii
Chris
Ben
Tomas
Ping
Sergey
Ekaterina
Andrew
Cameron
V.
P.
Brent
Catalin
Chengkun
Ritesh
Shuoqin
S.
G.
K.
X.
P.
A.
M.
Irina
Jerry
Seung Kim
Nikolai
Jean
Ohio State University
Princeton Plasma Physics
Laboratory
Stanford University
Stanford University
Stanford University
STI Optronics
University of Texas at Austin
University of California at Berkley
University of California Los Angeles
University of New Mexico
E.W. Collings
E. W. Collings
E. W. Collings
Gennady Shvets
Robert L. Byer
Robert L. Byer
Robert L. Byer
Wayne D. Kimura
T. Tajima
Jonathan Wurtele
Jonathan Wurtele
Jonathan Wurtele
D. Cline
D. Cline
Chan Joshi
Chan Joshi
Chan Joshi
Chan Joshi
Chan Joshi
Claudio Pellegrini
Claudio Pellegrini
Claudio Pellegrini
Claudio Pellegrini
Claudio Pellegrini
Claudio Pellegrini
Claudio Pellegrini
James A. Ellison
Tom Katsouleas
Tom Katsouleas
Tom Katsouleas
Tom Katsouleas
Last Name
First Name (MI)
Institute
Advisor.
1 Sumption
M.D.
E. W. Collings
2 Meng
3 Zwart
4 Zhang
Wuzeng
G. Townsend
Ge
5 Mahmoud
6 Papageorgiou
7 Bier
8 Wernick
Gamal
Vassilis
Martin
I.
Battell/Ohio
State
Boston Univ.
Boston Univ.
Clark
Univ./MIT
Clarkson
Clarkson
Clarkson
Columbia
9 Lin
L-Y
Columbia
T.C. Marshall
Crete
Carolina-Greenville
Columbia (Earth Sciences
Inst.)
1993 FOM Jutphaas (Neth. FEL) North Holland Publishing
10 Fang
11 Koyama
12 Adler
J-M
Taka
Richard
Columbia
Cornell Univ.
Cornell Univ.
T.C. Marshall
R. Talman
J. Nation
1997 Columbia
1999
1980 AFWL
13 Fenstermacher
14 Providakes
15 Anselmo
16 Greenwald
17 Sheffer
18 Koury
19 Davis
20 Kuang
21 Naqvi
Daniel
George
Antonio
Shlomo
Donald
Daniel
Timothy
Erjia
Shahid
Cornell
Cornell
Cornell
Cornell
Cornell
Cornell
Cornell
Cornell
Cornell
J.
J.
J.
J.
J.
J.
J.
J.
J.
Nation
Nation
Nation
Nation
Nation
Nation
Nation
Nation
Nation
1985 Harvard
1985 Mitre Corp
1987 Varian
1987 Israel Govt
1991 Duke
1992 Texas Instruments
1993 Kionix, Inc.
1994 Motorola, Far East
1996 U. Chicago Radiology Stu
22 Fletchner
Donald
Cornell Univ.
J. Nation
1999 Diamond Microelectronics
Diamond Microelectronics
23 Panek
John S.
Florida State
Univ./NHMFL
S. W. Van Sciver
1998 Jet Propulsion Lab/ Cal
Tech.
Goddard Space Flight
Center
24 Kurki
Taina
R. Huson
1989 UC-Berkeley
25 Tompkins
Perry
HARC/UTAustin
HARC/UTAustin
R. Huson
1990 Vanderbilt
Univ.
Univ.
Univ.
Univ.
Univ.
Univ.
Univ.
Univ.
Univ.
Krienan
Krienan
J. Davies
J. Wurtele
T. Bountis
T. Bountis
T. Bountis
T.C. Marshall
Year of First Placement
Ph.D.
1992 OSU
1991 BNL
1997 Bates
1993
Present Placement
OSU
BNL
Bates
Lorel Corp.
1988
1988
1990
1992 Rockefeller U.
Columbia
Intel
North Star Research, Inc.
Cornell University
Kionix, Inc.
Last Name
First Name (MI)
Institute
Advisor.
26 Kazima
Reza
R. Huson
27 Goodwin
28 Ellison
29 Minty
J.E.
T.
Michiko G.
HARC/UTAustin
Indiana U.
Indiana U.
Indiana U.
30 Pei
31 Ellison
32 Huang
33 Li
34 Nagaitsev
A.
M.
Haixin
Derun
Sergei
35 Kang
36 Riabko
37 Bai
38 Hoffstaetter
X.
A.
Mei
Georg
R. Pollock/Lee
S.Y. Lee
S.Y. Lee/A.
Krisch
Indiana U.
R. Pollock/Lee
Indiana U.
S. Y Lee
Indiana U.
S. Y. Lee
Indiana U.
S. Y. Lee
Indiana U.
P. Schwandt/
Lee
Indiana U.
S.Y. Lee
Indiana U.
S.Y. Lee
Indiana U.
S.Y. Lee
Michigan State Martin Berz
39 Wan
Weishi
40 Makino
Ph.D.
1992 JLAB
Present Placement
JLAB
1989 Fermilab
1990 IUCF
1991 SLAC
Software Industry
Energy Storage Industry
DESY
1992 BNL
1995 U. Colorado
1995 BNL
1995 UC San Diego
1995 Fermilab
Lucent
Industry
BNL
LBNL
Fermilab
1998 U. Washington
1998 Software industry
1999 BNL
1994 Univ. of Darmstadt
UC Davis
Software industry
BNL
DESY
1995 U. Colorado
ORNL
Kyoko
1997 Michigan State
Michigan State
41 Shamseddine
Khodr
1999 Michigan State
Michigan State
42 Ige
43 Conde
44 Chu
45 Menninger
O.O.
Manoel
Yiu
William
MIT
MIT
MIT
MIT
1989
1992 ANL
1993 VCR Plus
1994 Hughes Electron Devices
ANL
TRW Corp.
Hughes Electron Devices
46 Stoner
47 Yu
Richard
Xiao Tong
MIT
MIT
48 Lin
Chia-Lian
MIT
1994
1994 Long Term Capital
Management
1995 Torrey Communications
Philips Corp.
49 Shvets
Gennady
MIT
1995 PPPL
PPPL
Y. Iwasa
G. Bekefi
J. Wurtele
R.J. Temkin/
B.G.Danly
G. Bekefi
J. Wurtele
S. C. Chen/
A. Danly
J.Wurtele
J. Wurtele
Last Name
First Name (MI)
Institute
Advisor.
50 Hu
Wen
MIT
51 Trotz
Seth
MIT
52 Catravas
Palmyra
MIT
53 Volfbeyn
Pavel
MIT
54 Fink
Yoel
MIT
55 Gonichon
Jerome
MIT/
Univ. of Paris
56 Baine
Michael
NRL/UCSD
G. Bekefi/
R.J. Temkin
R.J. Temkin/
B.G. Danly
H. Haus /
J. Wurtele
W. Leemans /
J. Wurtele
C. Chen/ J.
Joannopoulos/
E. Thomas
C. Travier/ S.C.
Chen/ B.G.
Danly/ R.J.
Temkin
S. Ride, A. Ting,
P. Sprangle
57 Russell
58 Kingsley
59 Bamber
60 Bruhwiler
61 Gabella
62 Hendrickson
63 Stoltz
64 Li
65 Machida
66 Raparia
67 Zhang
68 Grossman
69 Douglas
70 Floyd
D. Patrick
Lawrence
Charles
David
William
Scott
Peter
Minyang
Shinji
Deepak
Peilei
John
David
Linton E.
Princeton
Rochester
Rochester
U. Colorado
U. Colorado
U. Colorado
U. Colorado
U. Houston
U. Houston
U. Houston
U. Houston
U. Maryland
U. Maryland
U. Maryland
71 Cremer
72 Forest
T.
Etienne
U. Maryland
U. Maryland
K. McDonald
A. Melissinos
A. Melissinos
J. R. Cary
J. R. Cary
J. R. Cary
J. R. Cary
S. Ohnuma
S. Ohnuma
S. Ohnuma
S. Ohnuma
C. Striffler
A. Dragt
M. Reiser, W.
Destler
W. Destler
A. Dragt
Ph.D.
1997 Goldman Sachs
1997 Dartmouth
Present Placement
Goldman Sachs
1998 LBNL
David Sarnoff Research
Center
LBNL
1998 LBNL
Harmonic, Inc.
2000 MIT
MIT, Faculty
1995 GE Medical Systems,
France
GE Medical Systems,
France
2000 Advanced Propulsion Lab,
NASA Johnson Space
Center
1992 U. Wisc/Med Phys
1990 U. Toronto
1991 Rochester
1990 Grumman
1991 Postdoc, UCLA
1996 Rogue Wave Software
1996 PPPL
1990 SSCL
1990 KEK
1990 SSCL
1991 SSCL
1981 NRL
1982 LBNL
1983 NRL
NASA Johnson Space
Center
1984 Industry
1984 LBNL
Army Lab-NJ
Tech-X Corp.
Vanderbilt FEL
Rogue Wave Software
Sandia Natl. Lab (Abq.)
KEK
NRL
TJNAF (CEBAF)
Industry
KEK HEP Lab
Last Name
First Name (MI)
Institute
Advisor.
73 Loschialpo
74 Milutinovic
75 Lawson
Peter F.
Janko
Wesley
U. Maryland
U. Maryland
U. Maryland
76 O’Shea
Patrick G.
U. Maryland
77 Schneider
Ralph F.
U. Maryland
M. Reiser
A. Dragt
W. Destler/
C. Striffler
W. Destler/
M. Reiser
M.J. Rhee
78 Healy
Liam
U. Maryland
A. Dragt
79 Chojnacki
80 Kehs
81 Ryne
82 Aghamir
83 Chang
84 Park
85 Bleum
86 Li
87 Rangarajan
Eric P.
R.A.
Robert
Farzin
Chu Rui
Gun-Sik
Hans
Rui
Govindan
U.
U.
U.
U.
U.
U.
U.
U.
U.
W. Destler
V. Granatstein
A. Dragt
W. Destler
M. Reiser
V. Granatstein
V. Granatstein
R. Gluckstern
A. Dragt
88 Zhang
89 Calame
Xiaohao
Jeffrey
U. Maryland
U. Maryland
90 Lou
Wei Ran
U. Maryland
91 Abe
92 Kehne
93 Tantawi
94 Fischer
95 Wang
96 Zhang
97 Meyers
98 Rappaport
99 Abell
David K.
David
Sami G.
Richard P.
Dunxiong
Zexiang
T.
Harold
Dan
U.
U.
U.
U.
U.
U.
U.
U.
U.
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
C. Striffler
V. Granatstein/
W. Lawson
V. Granatstein /
Y. Carmel
W. Drestler
M. Reiser
V. Granatstein
V. Granatstein
M. Reiser
V. Granatstein
W. Destler
C. Striffler
A. Dragt
Ph.D.
1984 NRL
1984 BNL
1985 U. Maryland
1985 LANL
Present Placement
NRL
Wall Street
U. Maryland, Faculty
U. Maryland, Faculty
1985 Defense Threat Reduction Industry
Agency
1986 CERN
NRL, Celestial Mechanics
Group
1987 ANL
Cornell
1987 LLNL
LLNL
1987 LLNL
LBNL
1988 UCLA
UCLA
1989 SSCL
Industry
1989 Seoul Natl. Univ., Korea
Seoul Natl. Univ., Korea
1990 Industry
Industry
1990 TJNAF (CEBAF)
TJNAF (CEBAF)
1990 LBNL
Mathematics Faculty,
Indian Institute of Science,
Bangalore
1990
1991 NRL
NRL
1991 Lucent Tech.
Lucent Tech.
1992 NRL
1992 TJNAF
1992 SLAC
1993 NRL
1993 TJNAF
1993 Lucent Tech.
1994
1994 U. Texas
1995 BNL
NRL
FM Technologies
SLAC
NRL
TJNAF
Lucent Tech.
U. Texas
BNL
Last Name
First Name (MI)
Institute
Advisor.
100 Brown
101 Cheng
102 Allen
103 Jiang
104 Suk
105 Fedotov
106 Clark
Nathan
Wen-hao
Chris
Shicheng
Hyyong
Alexei
Thomas
U.
U.
U.
U.
U.
U.
U.
M. Reiser
R. Gluckstern
M. Reiser
A. Dragt
M. Reiser
R. Gluckstern
T. Antonsen
107 Nikitin
108 Venturini
Sergei
Marco
U. Maryland
U. Maryland
109 Bernal
110 Zou
111 Schuett
Santiago
Yun
Petra
112 Goodwin
113 Anferov
114 Shoumkin
115 Chu
116 Koulsha
117 Van Guilder
118 Blinov
119 Alexeva
120 Crandall
121 Varzar
122 Abedi-Khafri
123 Watanobe
124 Chen
125 Fisher
J.E.
V.A.
D.S.
C.M.
A.V.
B.
Boris
L. V.
D. A.
S. M.
M.
Hiroshi
Li
David L.
U. Maryland
U. Maryland
U. Maryland/
Hamburg
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Michigan
U. Oregon
U. Oregon
U. Oregon
U. Texas
T. Antonsen
A. Dragt /
M. Reiser
M. Reiser
M. Reiser
A. Dragt/
T. Wailand
Krisch
Krisch
Krisch
Krisch
Krisch
Krisch
Krisch
Krisch
Krisch
Krisch
Csonka
Csonka
Csonka
T. Tajima
126 Ottinger
127 Chen
128 Hawksworth
Michael
X.M. Jerry
David G.
U. Texas
U. Texas
U. Wisconsin,
Madison
T. Tajima
T. Tajima
D. C.
Larbalestier
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
Ph.D.
1995 Gillespie Assoc.
1995 LBNL
1996 Industry
1996 Cable and Wireless, Inc.
1996 UCLA
1997 BNL
1998 NRL, Optical Science Div.
Present Placement
Industry
Intel, Inc.
LANL
Cable and Wireless, Inc.
UCLA
BNL
NRL, Optical Science Div.
1998 Quantronix Corp.
1998 SLAC
Quantronix Corp.
SLAC
1999 U. Maryland
2000 Industry
1988 TU, Darmstadt
U. Maryland
Industry
GSI, Darmstadt
1990 Fermilab
1992 IHEP
1993 IHEP
1994 IUCF
1994 Industry/Russia
1994 Montclair State College
1995 U. Michigan
U. Michigan
1996 IHEP
1996 Industry
1996 IHEP
1985
1985 Colgate Univ.
1992
1995 Applied Research Lab UTA Applied Research Lab
1997 Turman State U.
1999 Dupont Photmaks
1981 Oxford Magnet Tech.
Turman State U.
Oxford Magnet Tech
Last Name
First Name (MI)
Institute
Advisor.
129 Marken
Kenneth R.
130 Maddocks
James
D. C.
Larbalestier
S. W. Van Sciver
131 Smathers
David
132 Moffat
David
133 Larson
Delbert
134 Warnes
William H.
135 Rosenzweig
James
136 Holmes
D. Scott
137 Meingast
Christopher
138 Muller
Henry
139 Weisand, II
John G.
140 Daumling
Manfred
141 McKinnell
Jim
142 Seuntjens
Jeff
143 Buckett
Mary
144 Daugherty
Mark A.
145 Hampshire
Damian
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
D. C.
Larbalestier
D. C.
Larbalestier
D. Cline/F. Mills
D. C.
Larbalestier
D. Cline /
J. Simpson
S. W.
Van Sciver
D. C.
Larbalestier
D. C.
Larbalestier
S. W. Van Sciver
D. C.
Larbalestier
D. C.
Larbalestier
D. C.
Larbalestier
D. C.
Larbalestier
S. W. Van Sciver
D. C.
Larbalestier
Ph.D.
1986 NIM Japan
Present Placement
Batelle-Columbus
1991
1983 Teledyne Wah Chang
TOSHOH SMD
1985 Was in the field
Madison Software Co.
1986 U. Wisconsin
SAIC
1986 Oregon State University,
Faculty
1988 ANL
Oregon State University,
Faculty
UCLA
1989 Lake Shore Cryotronics
Consulting
1989 ITP, Forschungszentrum
Karlsruhe, Germany
1989
ITP, Forschungszentrum
Karlsruhe, Germany
Midwest Superconductors
1989 SSC Laboratory
Cryogenics at SLAC
1990
NKT Research Center
1990 Oxford Superconducting
Technology
Technology
1991 3M
HP
1991 Los Alamos Natl.
Laboratory
1991
Private practice
Singapore Fine Wire
POHANG (Check Asc’00
attendee list)
Last Name
First Name (MI)
Institute
Advisor.
Ph.D.
1991 SSCL
Present Placement
146 Palkovik
John
147 Stejic
George
148 Bonney
Laura
149 Cooley
Lance
150 Huang
Xiaodong
D. Cline/
F. Mills
D. C.
Larbalestier
D. C.
Larbalestier
D. C.
Larbalestier
S. W. Van Sciver
151 Huang
Yuenian
152 Jablonski
Paul
153 Heussner
Robert
154 Kadyrov
Earnest (Eric)
155 Parrell
Jeff
156 Cole
Benjamin
157 Schoeder
158 Golden
Carl
Fletcher
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison
U. Wisconsin,
Madison /
North Texas
State
UC Berkley
UC-Irvine
1993 Eaton Corp.
Tesla Laboratories
1994 FSU – NHMFL
Johns Hopkins University
1994 NRC Fellow- NIST
U. Wisconsin, Madison
1994 NHMFL
Position in finance
S. W. Van Sciver
1994 Fermilab
Fermilab
D. C.
Larbalestier
D. C.
Larbalestier
D. C.
Larbalestier
D. C.
Larbalestier
D. Cline/F. Mills
1994 Teledyne Wah Chang
Precision Castparts Airfoils
159 Irans
Ardeshir
UC-Irvine
160 Darrow
161 Figueroa
162 Mori
163 Umstadter
164 Wilks
165 Leemans
Chris
Humberto
Warren
Don
Scott
Wim
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
J. Wurtele
Fisher/
Rostoker
Fisher/
Rostoker
C. Joshi
C. Joshi
C. Joshi
C. Joshi
C. Joshi
C. Joshi
1997 HP
1997 Hewlett-Packard
Hewlett-Packard
Technology
1992 SSCL
1993
1999 UCLA
1985 EG&G
UCLA
1985 BNL
1986 LLNL
1986 ANL
1987 Rutherford Laboratory
1987 Bell Labs
1989 LLNL
1991 LBL
LLNL
ITT Venezuela
UCLA
U. Michigan
LLNL
LBL
Last Name
First Name (MI)
Institute
Advisor.
166 Robin
167 Wong
168 Moore
169 Sakawa
170 Savage, Jr.
171 Wang
David
W. H.
James M.
Youichi
Richard
Xijie
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
172 Williams
173 Hartman
174 Decker
175 Everett
176 Brogle
177 Davis
178 Lal
179 Smolin
180 Travish
181 Colby
182 Ramachandran
Ronald
Spencer
Chris
Matt
Robert
Joseph (Pepe)
Amit
John
Gilbert
Eric
Sathyadev
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
183 Zhang
184 Barov
185 Hogan
186 Terebilo
187 Tzeng
188 Wharton
189 Gordon
190 Tremain
191 Duda
192 Hemker
193 Ho
Renshan
Nikolai
Mark
Andrei
Kuo-Cheng
Ken
Dan
Aaron
Brian
Roy
Ching-Hung
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA
UCLA/ANL
194 Liu
Yabo
UCLA/BNL
C. Pellegrini
Clark
Clark
C. Joshi
C. Joshi
D. Cline/
I. Ben-Zvi
C. Joshi
C. Pellegrini
C. Joshi
C. Joshi
C. Joshi
C. Joshi
C. Joshi
C. Pellegrini
J. Rosenzweig
J. Rosenzweig
D. Cline/
T. Murphy
(FNAL)
C. Pellegrini
J. Rosenzweig
C. Pellegrini
C. Pellegrini
C. Joshi
C. Joshi
C. Joshi
J. Rosenzweig
C. Joshi
C. Joshi
D. Cline/
J. Simpson
D. Cline/
I. Ben-Zvi
Ph.D.
1991 LBNL
1991 UCLA
1992 IBM
1992 Nagoya U.
1992 CalTech
1992 BNL/UCLA
1992 Florida A&M
1993 SLAC
1994 LLNL
1994 LLNL
1996 Aeroject, Inc.
1996 Optiphase Inc.
1996 Metrolaser, Inc.
1996 IBM
1996 UCLA
1997 SLAC
1997 FNAL
1997 Hughes Corp.
1998 UCLA
1998 SLAC
1998 SLAC
1998 Investment Banking
1998 LLNL
1999 NRL
1999 UCLA
2000 Lincoln Labs, MIT
2000 U. of Tokyo
1992 Taiwan
1997 UCLA
Present Placement
LBNL
Nagoya U.
CalTech
BNL
Florida A&M
Opti-Phase Corp.
LLNL
Private Industry
Optimight, Inc.
Optiphase, Inc.
Metrolaser, Inc.
IBM
ANL
SLAC
Univ. Houston
UCLA
SLAC
SLAC
LLNL
NRL
UCLA
Lincoln Labs, MIT
U. of Tokyo
Taiwan
UCLA
Last Name
First Name (MI)
Institute
Advisor.
195 Rajagopalan
Sankaranaray
UCLA/SLAC
196 Nantista
Christopher
197 Lin
198 Gou
Xin-Tian
S. K.
199 Lai
C.H.
D.Cline/
P. Chen
UCLA/SLAC
D. Cline/
T. Lavine
UCSD
N. Kroll
U-IA/Columbia Amitava
Bhattacharjee
USC
T. Katsouleas
200 Chiou
201 Ahn
T.C.
Hyo
USC
Yale
T. Katsouleas
V. Hughes
Ph.D.
1993 UCLA
Present Placement
Industry
1994 SLAC
SLAC
1995
2000 Semiconductor Industry
Semiconductor Industry
1997 Industrial Technology
Investment Corp.
1998 Qualcom
1992
Star Capital Group
Qualcom

here - High Energy Physics Group

Transcription

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