Relativistic heavy ion collider (RHIC) accelerator facility

Transcription

Relativistic heavy ion collider (RHIC) accelerator facility
RHIC:The Path Forward
Presented to
Quark Matter 2006
Shanghai, PRC
Derek I. Lowenstein
Brookhaven National Laboratory
November 15, 2006
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The Present RHIC
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RHIC – a high luminosity hadron collider
PHOBOS
BRAHMS
Jet Target
Electron cooler
RHIC
PHENIX
STAR
LINAC
RF
NSRL
Booster
EBIS
AGS
Achieved peak luminosities (100 GeV, nucl.-nucl.):
Au–Au
581030 cm-2 s -1 (2x design)
p–p
351030 cm-2 s -1 (7x design)
Other large hadron colliders (scaled to 100 GeV):
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Tevatron (p – pbar)
251030 cm-2 s -1
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LHC (p – p, design) 1401030 cm-2 s -1
Operated modes (beam energies):
Au–Au
10, 28, 31, 65, 100 GeV/n
d–Au*
100 GeV/n
Tandems Cu–Cu
11, 31, 100 GeV/n
p–p
11, 31, 100, 205, 250 GeV
Possible future modes:
Au – Au 2.5 GeV/n (AGS, SPS
c.m. energy)
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p – Au* 100 GeV/n (*asymmetric rigidity)
Delivered luminosity and polarization during last 5 years (Q3)
65%
47%
46%
34%
15%
 Expect x2 Au ion luminosity increase in the 2007 run
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The Evolution of RHIC
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Path Forward
Short

term (2007-2008)
Luminosity increase

Stochastic cooling complete

Increase number of bunches

Mid


>x2 for ions; >x2 for polarized protons
term (2009-2010)
RHIC II Phase 1 efforts completed

EBIS injector operational

Major detector upgrades completed
RHIC II Phase 2 efforts started

Longer
electron cooling construction started
term (2011-2015)

RHIC II completed

eRHIC Project started
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Goals for RHIC Enhanced Design Performance (2008*)
1. Au-Au
L store average= 8 x 1026 cm-2s-1 @ 100 GeV/n
2. p  -p 
L store average=150 x 1030 cm-2s-1 @ 250 GeV
3.
P store average = 70%
4. 60% of calendar time in store = 100 hours/week
5.
*First 250 GeV p-p physics run currently scheduled for 2009.
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Stochastic cooling of a high
frequency bunched beam has
been observed for the first time.
Stochastic cooling can counteract IBS by
keeping the emittance constant while
electron cooling will shrink the emittance.
Improves RHIC performance by providing
more luminosity (20-50%) improved vertex
size, and longer stores and reduced
number of refills. Improves productivity.
Time domain (oscilloscope) and frequency
domain (spectrum analyzer) measurements
confirm cooling
Cooling time about 1 hour
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Bunch profile before (red) and after (blue)
cooling, Wall Current Monitor
Schottky spectrum before cooling: blue trace
Spectrum after cooling: red trace
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EBIS Injector Project

New RHIC preinjector system: EBIS replaces 30+ year old tandems
 Joint DOE and NASA funded project. Construction begun in 2006.
 Improves performance
 Extends mass range to uranium
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 Allows for polarized He injection
 Commission in 2009
EBIS test stand
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Why RHIC II ?
The RHIC experiments have learned to utilize elemental QCD
processes generated in the collisions themselves, such as…
• formation and transport of heavy quarks, and quarkonium bound states
• fragmenting jets from high energy partons
q
• high energy photons
q
Typically these are rare probes:
Future progress requires well-defined improvements in detector
capability and machine performance.
T. Ludlam
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RHIC II electron cooling
Electron cooling of ion beams
Increases the luminosity for heavy ions by a factor of ten
 Based on a high energy, 54 MeV and 50 mamp, energy recovery
linac (ERL) and a superconducting photoelectron gun
 Preparing for DOE CD0 decision in early FY2007
Superconducting RF Cavity
Ampere Superconducting RF Gun
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Electron-cooling facility at IP2
Electron cooling
R&D
Cooling
region
RHIC
triplet
100 m
RHIC
triplet
ERL
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Why eRHIC?
A New Generation of DIS:
High luminosity polarized Electron-Nucleon/Electron-Ion Collider
Electron-proton collisions
• Gluon and sea quark polarization
• The role of orbital angular momentum
Electron – Ion collisions
• Gluon momentum distributions in nuclei
• Gluons in saturation
• The color glass condensate
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eRHIC at BNL
A high energy, high intensity polarized electron (and positron) beam to
collide with the existing heavy ion and polarized proton beam.
Would significantly enhance RHIC’s ability to probe fundamental,
universal aspects of QCD
•Ee = 10 GeV (~5-12 GeV variable)
•Ep = 250 GeV (~50-250 GeV variable)
•EA= 100 GeV/nucleon (for Au)
•At least one new detector for ep & eA
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TO BE BUILT
EXISTS
EXISTS
TO BE BUILT
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eRHIC Design Concepts
2 designs are under consideration
Ring-Ring design
Linac-Ring design
simpler ring design
one IR possible
less R&D effort
1033 luminosity
simpler IR design
multiple IRs possible
Ee ~ 20 GeV possible
1034 luminosity
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eRHIC CM Energy vs Luminosity
eRHIC
Jlab12GeV



eRHIC

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Variable beam
energy
Proton-to-uranium
ion beams!
Proton, He3(EBIS)
polarization
1034 luminosity
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eRHIC ZDR
http://www.bnl.gov/eic
Reviewed June 2005 (252 page
document)
Collaboration: BNL, MIT-Bates, BINP
& DESY
Goals: initial design, identify &
investigate most crucial R&D
problems for challenging
luminosities and IR design
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Path Forward Schedule
RHIC II
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