Isis TS2 News8 - Science and Technology Facilities Council

news from the ISIS second target station project
I ssue 8 Oc t ob e r 2 00 7
The pace of progress in building the Second Target
Station during 2007 has been impressive. Substantial
quantitites of equipment have been installed and tested
in preparation for the ISIS target station to generate its
first neutrons for commissioning experiments in Spring
2008.
During the summer months, several major successes have
been achieved by the project. The 6000 tonne steel and
concrete monolith structure to house the neutron target
was completed, and the proton beamline stretching from
the synchrotron to the target station was installed.
Meanwhile, cryogenic cooling systems for the neutron
target assembly passed their performance tests in France
and have been delivered to the site. The beryllium reflector
that will surround the target to increase neutron yield has
arrived from the United States.
Instrument shielding rooms have been constructed and the
large vacuum tank for the Sans2d instrument is in position.
Components for the Offspec reflectometer, developed in
collaboration with the Technical University of Delft, have
been successfully tested with neutrons.
1
1 OCT 06
Surveying magnet location plates as the proton
beam tunnel is constructed
2 OCT 06
Hundreds of metres of stainless steel pipework
has been installed to supply cooling water
3 NOV 06
Quadrupole magnets are carefully aligned by
Adrian Hooper
4 JAN 07
Only with proton tunnel walls in place can
services be installed
6 APR 07
5 MAR 07
The first magnet was installed in
March 2007
Hundreds of tonnes of steel in the holding yard
at ISIS
7 JUL 07
Final adjustments to connections on the
vacuum seals on the proton beam tube
8 JUL 07
9 JUL 07
Inside the completed proton beam tunnel, the line of magnets stretches off towards the target station
2
View towards the synchrotron
At a short ceremony in
March 2007, ISIS
Director Andrew
Taylor gently lowered
the first magnet for
the extracted proton
beam onto a support
plinth. Five months
later, the beamline was
completed.
“All of the teams working on the project over the spring and
summer months have done a fantastic job. It has been
incredible watching empty experimental halls turn into a
recognisable new science facility,” said ISIS Director,
Andrew Taylor.
Proton beamline tests are scheduled to take place in
December 2007. Protons will travel at 84% light speed along
the 143 m beamline from the synchrotron to the target, guided
and focussed by 57 magnets manufactured by specialist
European engineering companies Scanditronix, Danfysik,
SigmaPhi and Budker. The proton beam will travel inside a
stainless steel vacuum tube evacuated to over a million times
less than atmospheric pressure.
Before the first magnet could be installed, the shielding walls
of the proton beam tunnel were erected. Around 23,000
tonnes of steel have been used in the 1.5 m thick tunnel walls
to protect against radiation. Only after the shielding walls were
completed, could electrical services and pipework for water be
installed.
With each magnet in position, teams of surveyors corrected
the alignment before technicians connected the electricity and
cooling water supplies. Each magnet installation took between
four and five days to complete.
Proton Beam Task Leader
Beam diagnostics
Matt Fletcher
Tony Kershaw, Eamonn Quinn
Kicker magnets
Steve Jago, Eamonn Quinn
Septum magnet
Steve Jago, Stuart Birch
Bending magnets proton beam 1
Les Jones
Bending magnets proton beam 2
Mark Westall
Electrical engineering
Steve Stoneham, Stuart Birch,
Adrian Morris
High current electrical busbars
Water cooling
John Govans, John Corkhill
Shielding
Trevor Pike
Equipment interlocks
Vacuum
Mark Arnold, Peter Gear
Shaun Hughes, Geoff Matthews
Electromagnetic design
Installation Contract Manager
Beam optics design
Magnet alignment
John Teah
Steve Jago, Dan Faircloth
Peter Hoogewerf, Alstec
Dean Adams
Jim Loughrey, Adrian Hooper,
Ray Corderoy, Mark Ashman, Brett Clark
3
4
After seven months of installation and two months of testing, the first
components of the second target proton transport beamline are
working successfully. These components are shared with the proton
transport beamline to Target Station One. The first ISIS user run cycle
of 2007 began on 9 October with the accelerator delivering 165 µA
proton beam current to the target.
The start of 2007 was an exciting and anxious time
for ISIS staff working on this section of the project.
This was the first time in over 20 years of operation
that this section of the accelerator would be
worked on.
Matt Fletcher, Task Leader for proton beam
installation, was highly confident that all would go
well, taking reassurance from recent successful
projects refurbishing other sections of the ISIS
accelerators.
“To be absolutely sure we knew where everything
was located, we added substantial information to
existing plans by extensively surveying the current
beamlines before we dismantled them,” he said.
“We had everything as prepared as we could. But
since the original drawings of this area were wellover 20 years old, in the back of my mind, I was
always wondering how accurate those drawings
were.”
The extracted proton beam line flies over the
synchrotron to send proton bunches from the
synchrotron accelerator to the target station. Protons
in the evacuated beam tubes are travelling at 84%
light speed.
septum magnet to divert proton bunches into the
new beamline, two quadrupole focusing magnets,
and a smaller bending magnet to enable beam to be
delivered to Target One.
“We mounted magnet frames onto the original
concrete support plinths in the synchrotron even
though this made the job slightly more difficult. We
opted to carry out the minimum amount of work near
the synchrotron, since modifying the support plinths
would cause lot of dust and debris, and could
possibly damage the accelerator,” said Fletcher.
With around 12 different teams working in very close
proximity, Fletcher identifies clear lines of
communication between all the team members as
the key to success.
“Due to the difficult access, not everything could be
decided six months in advance. So we held weekly
meetings in the area with everyone involved so we
could be as close to the job as possible,” he said.
“Everyone took ownership of their part in the project
and solved issues quickly. It really makes a
difference when people recognise the prestige of the
project and take pride in getting the delivery quality
right.”
Fletcher’s team started by removing a 15 m length of
magnets and diagnostic equipment in the
synchrotron room. At the same time, demolition
crews began to remove 10 m thick concrete and
steel shielding walls between the synchrotron room
and the new link building connected to the Second
Target Station.
Now the pressure was on to complete the installation
before the 1 August 2007. Working in the extraction
area is not straightforward as the main synchrotron
accelerator runs directly below and could not be
disturbed. Sufficient time was needed to ready the
synchrotron and extracted proton beamlines for the
October user run cycles.
Breakthrough into the synchrotron room.
Two focusing quadrupole magnets and two beam
steering magnets were removed. Into the same
space were placed two slow kicker magnets and a
5
1 Installing the septum
power supply
1
2
3 Busbars link to the
septum magnet in the
synchrotron room
2 Copper busbars carry
power to the septum
magnet
3
4
4 Over a million cable
terminations are
needed in the project
6
5
5 Thousands of metres
of electrical cable
have been pulled into
place
Electrical Engineering is
critical to the success of
the Second Target Station
Project.
Electricity is everywhere in the project:
supplying kilowatts of power to the
proton beam magnets; feeding real-time
beam position data and beam control
signals to and from the accelerator main
control room; monitoring temperature and
water flow in the target station; motion
control for neutron instruments; and
streaming neutron counts from neutron
detectors to data processing hubs.
“Electrical engineering can be thought of
as the nervous system of the whole
project,” said Steve Stoneham, Electrical
Engineering Task Leader. “It connects
everywhere in the project, and without it
nothing would be able to operate. It is an
enormous task to keep on top of all the
power and signal cables – not just the
numbers but where they are all routed.
“You can appreciate the size of the task
just by contemplating that there are more
than one million individual cable
terminations to be made. Everything we
are doing here is to industry-leading
specifications, so the Second Target
Station Project has an electrical system
that it can be extremely proud of.”
For the beam optics in the extracted
proton beamline, 56 DC power supplies
ranging from 4kW to 250 KW are needed
in addition to the 650 kW septum magnet
and two 10 Hz slow kicker pulsed magnet
supplies.
Septum
One of the most critical areas of the task
has been supplying power to the septum
magnet. The two-chambered magnet
gives a five degree beam deflection to the
proton beam into the extraction beamline
for the second target station.
The high current, high power device has
one chamber requiring a high magnetic
field produced by an 8650 amp current
circulating though a 14 turn coil, whilst the
second chamber does not need a
magnetic field. The two tonne device built
by French manufacturer SigmaPhi is water
cooled at a rate of 380 litres a minute.
Power to the septum
magnet is supplied from a newly built
substation via 24 power converters using
the latest semiconductor IGBT
technology for reliability and efficiency.
The power converters occupy 14 square
metres, are 93% efficient and can supply
up to 10,000 amps to the septum
magnet. A current feedback element
compares measured current with set
current to ensure that the stability is
better than 100 parts per million.
Busbars made from oxygen free, highconductivity copper carry the current
through service trenches into the
synchrotron room to connect to the
septum magnet. Around 16.5 kW heat is
generated in these 60 mm tubular bars, so
cooling water is pumped through the
central cores at around 100 litres a minute.
7
The size of a railway
carriage, the vacuum
tank for the Sans2d
instrument was
delivered to ISIS in
March. It was the first,
and one of the largest,
major instrument
components to arrive.
Small-angle neutron scattering
is a powerful technique for
determining the size and
distribution of scattering
objects with sizes from
nanometres to microns.
The 13 m long, 3.25 m
diameter vacuum tank will
house two square multiwire
detectors manufactured by
Ordela in the United States.
1
1 The Sans2d
vacuum tank is
lowered into place
2 Richard Heenan,
Instrument Scientist,
welcomes the tank as
it arrives from The
Netherlands
3 David Turner,
Instrument Engineer
8
2
3
Designers of the
Wish powder
diffraction
instrument intend
that a single
measurement will
yield all of the
information
required to solve
the magnetic and
crystal structures
of a sample.
Wish will operate by delivering a highflux of long-wavelength neutrons along
an elliptical neutron guide to the
sample. Position-sensitive detectors to
collect the diffraction patterns
surround the sample.
Meeting this requirement has proved a
challenge for the engineering design team
since all of the components are nonstandard.
“To allow the detectors to get a clear view
of the sample, the sample vacuum tank
requires vacuum windows giving 160º
visibility either side of the main beam,
which leaves just 20º to get the beam in
and out,” said Wish engineer Chris
Benson.
“The wide-angle windows place tight
constraints on the engineering design of
the support structure,” he said.
“We’ve opted for stainless steel for
strength and stiffness and also because
it’s non-magnetic, so there will be no
interference with the high magnetic fields
at the sample position.”
Wish detectors are placed on a very
specific curve around the sample position
with the vacuum windows curving in the
same way. This adds the extra
complication of a curved sealing face.
Nevertheless, the design has been
proven, with vacuum windows
successfully completing 10,000
evacuation cycles to test their durability.
The vacuum tank design was optimised
with finite element analysis to ensure the
structure could withstand the forces when
evacuated. In addition to the unusual
shape, it also includes space for the 14
tesla magnet and a radial collimator to
reduce the background scattering signal.
An argon flight path vessel sits between
the sample vacuum tank and the
detectors. The detector mounting
assemblies can roll outwards to enable
servicing of the vacuum tank windows.
Prototypes of 3He detector tubes, with a
new design of just 8 mm diameter,
successfully completed tests in
December 2006. Manufactured by
Reuter-Stokes, 750 of the metre long
position-sensitive detectors have been
ordered.
9
Magnets for Offspec each weigh
500 kg, so rugged optics benches
are necessary to move the
magnets around inside the
instrument.
Nick Webb, instrument engineer for
Offspec and Polref, has designed
benches that will position loads of over
1 tonne to an accuracy of 100 microns.
“Of all the things in the instrument, I’m
most pleased with the benches,” he said.
“The specification for the 2.5 m long
benches needed them to have minimal
deflection when moving the equipment
around. The bench load is required to
move up and down and tilt. During
testing, a positional accuracy of 50
microns was recorded, with incremental
motions of less than 10 microns. An
excellent result.”
Two of Europe’s largest cosmetic
wax manufacturers are among the
more surprising contractors
working with the Second Target
Station Project. Whilst normal
business focuses on supplying the
beauty industry with waxes for
body hair removal and hair
styling, or the food industry for
cheese coatings, Darent Wax and
Paramelt are also expert suppliers
of neutron shielding.
Neutron shielding surrounding the
instruments at the Second Target Station
Project is a mix of boron and paraffin
wax. Paraffin wax contains a lot of
hydrogen and hydrogen has the largest
interaction with a neutron of any element
in the periodic table. Neutrons entering
10
Sean Langridge, Group Leader for
the reflectometer instruments,
explained that engineering
accuracy at this level is crucial for
the science programme.
“Reproducibility at these levels is
essential for us to ensure that the spinecho signal for Offspec is just right,” he
said. “If the optics benches are out of
position by even the smallest amount,
then the whole instrument has to be retuned for each experiment. These new
optics benches are incredible and it’s
important to
remember that you
can’t just go out
and buy this
equipment. Both of
these new
reflectometers will
be unique in the
world.”
the shielding lose energy by colliding with
hydrogen atoms and are absorbed by the
boron.
pieces to be filled, we reckon on needing
around 707 tonnes of wax over the
lifetime of project,” he said.
Leigh Perrott, Project Manager for the
Wish and Nimrod instruments, oversees
the wax shielding contracts. “Each
shielding piece takes around one week to
be filled,” he said. “The filling is made in
layers since the wax shrinks on
cooling. When we’ve finished,
we’ll have been filling shielding
tanks for around two and a half
years.”
That’s enough wax for 14 million
beautifully smooth and hair free legs!
“We have to dovetail the filling
of the shielding with the
manufacturers schedules
so as not to upset the
summer demand for
wax products. With
over 350 shielding
Increasingly, science and
technology applications
based on interfaces, thin
films and multilayers will
depend on knowledge of
structures in the plane of
the interface.
Offspec is an advanced reflectometer
giving access to nanometre length scales
parallel and perpendicular to interfaces. It
uses the technique of spin-echo to
decode the path that neutrons take
through the instrument.
The length scale coverage of Offspec will
be comparable to those studied by
atomic force microscopy, scanning tunnel
microscopy and other more invasive
surface profiling techniques.
Neutron reflectometry offers unique
advantages over techniques such as
scanning probe microscopy and grazing
incidence X-ray diffraction – in particular,
the ability to study buried interfaces and
to give information on composition
profiles perpendicular to an interface.
First spin-echo results
By enabling the explicit separation of
specular and off-specular reflectivity,
Offspec will allow new surface structures
such as patterned data storage media,
mesoporous films and biological
membranes to be studied.
Offspec relies on rotating polarised
neutrons in magnetic fields to give
extremely high sensitivity and allow the
explicit separation of different signals
from the sample with very high resolution.
The ISIS Second Target Station Project is
working in close collaboration with
experts in spin-echo technology from the
Interfaculty Research Institute of the
Technical University of Delft, The
Netherlands.
First Offspec spin-echo spectrum
The manufacture of the spin-echo
component of Offspec is progressing
extremely well and has been assembled
at Delft before its installation at ISIS.
The Delft team have been putting the
components through their paces using
neutrons from the Delft research reactor.
At the end of May, Jeroen Plomp, Victor
de Haan and Ad van Well collected the
very first data at Delft from the
instrument. Whilst the initial results were
limited by the polarisation of the neutron
beam polariser, they nevertheless
demonstrate the excellent progress that
the group has made in developing this
complex instrument.
First white beam spin-echo group
1.0
1.0
0.8
0.8
0.6
0.4
Polarisation
0.6
0.2
0.4
0
-0.2
0.2
-0.4
-0.6
0
-0.8
-0.2
0
0.1
0.2
0.3
0.4
0.5
Lambda (nm)
0.6
0.7
0.8
0.9
-1.0
3.6
4.1
Echo balance field
4.6
11
1 SEP 06
2 OCT 06
7 FEB 07
6 JAN 07
3 NOV 06
4 NOV 06
5 JAN 07
8 MAY 07
9 MAY 07
12 AUG 07
11 JUL 07
10 JUN 07
13 SEP 07
16 SEP 07
12
14 SEP 07
15 SEP 07
Neutron
moderators and a
cryogenic system
lie at the heart of
the Second Target
Station. By
slowing down
neutrons released
from the target
to speeds useful
for experiments,
the unique design
of this new target
and moderator
system will yield
four times more
neutrons than the
current ISIS
target station for
the same number
of protons onto
the target.
The Second Target Station has two
cryogenic moderators. Above the target is
a solid methane ‘decoupled’ moderator,
whilst below the target, a ‘coupled’
moderator combines liquid hydrogen at
20 K and solid methane at 26 K. Coupling
refers to the widths of the final neutron
pulses leaving the moderator: the
decoupled moderator produces sharper
neutron pulses than the coupled
moderator.
Radiation damage in methane produces
hydrogen gas that has to be released
regularly through a controlled warming, or
annealing, of the moderator to avoid
bursting. Loss of methane in this way
reduces performance, so methane in the
moderator will be replaced regularly.
The cryogenic design developed by
Stuart Ansell, Marc Simon, David Jenkins
and Sean Higgins allows for an anneal
time of less than one hour every 24 hours
and charge change of less than three
hours every three days.
Helium gas is compressed to 15 bar and
passed through cold boxes containing
refrigerators and heat exchangers to cool
the gas to 20 K. The decoupled
moderator is then cooled directly by the
helium gas. In the coupled moderator, the
helium gas is used to cool the liquid
hydrogen circuit, which in turn cools the
solid methane.
“There are complex design issues in this
system relating to the heat transfer,
radiation damage and explosive gases,”
said cryogenics engineer Marc Simon.
“We have had to design the entire system
within the regulations relating to the
handling of explosive atmospheres. Since
access into the target area is so difficult,
we have kept everything as simple as
possible unless there was a large
associated improvement in the neutron
output,” he said.
Simon and Higgins have tested the entire
cryogenic system at the Sassenage site,
in the French Alps, of cryogenic
engineering company Air Liquide. This
same site was used to test the liquid
hydrogen rocket engines for the Arianne 5
launchers used by the European Space
Agency, so the team were in good hands.
Hydrogen
buffer
Moderators
Arianne 5
hydrogen
rocket engine
test tower
Cryogenic
transfer
lines
Marc Simon and
Sean Higgins in
blast proof
control bunker
Hydrogen
and helium
cold boxes
In March 2007, standing in a freezing
blast-proof bunker, Simon and Higgins
proved that the entire system operated to
specification.
“It was very impressive and it proved that
all of our calculations were correct,” said
Simon. “Air Liquide have built in some
very elegant technology to manage the
gas and liquid pressures in the system.
We’re really looking forward to installing
and commissioning the system at ISIS
over the coming months.”
13
Ed Vaizey, Member of Parliament for Wantage and Didcot, visited the Second Target Station Project in
February to check out progress. With ISIS the world’s leading neutron source, the AstraGemini and Vulcan
lasers and the Diamond Light Source, the MP’s constituency is now the big-science capital of the UK.
“The ISIS building is astonishing,” he wrote later on his
constituency blog. “The central structure which weighs 6,000
tonnes and cost £10 million could easily be mistaken for a
monumental installation, which says something about the thin
line between art and science.
“ISIS 2, which comes twenty years after ISIS 1, is in a building
designed to make science accessible. The designers, while
dealing with a fiendishly complex structure, didn’t forget a
coach park and viewing platform for children. So while
we moan about the state of science in our schools, it
is good to know that our world-beating scientists
always have the next generation in mind whatever
they do.”
Ed Vaizey MP (left) visited the project in February with
ISIS Director, Andrew Taylor
Project Scientist Jeff Penfold has been awarded the 2007 Hälg Prize of
the European Neutron Scattering Association in recognition of his
ground breaking work on neutron reflection, which he developed as
an invaluable tool in colloid and interface science.
“These achievements have only been
possible because of some important and
fruitful collaborations with industry,
universities, and colleagues at ISIS and
other facilities over a number of the
years,” Professor Penfold said.
The Association cited his work on
instrument and technique development as
well as a large volume of highly original
research as the basis for the award. In
particular, Penfold has played a
pioneering role in the development of
neutron reflection and has exploited this
14
technique, combined with small-angle
neutron scattering in order to provide a
complete picture, for studies of surface
chemistry
More recently, his work has focused on
revealing unexpected phenomena of both
fundamental and practical interest in the
study of complex surfactant mixtures, the
interactions between polyelectrolytes and
surfactants, and between biological
molecules and surfactants.
ISIS is in the process of defining the second phase of
instruments for the Second Target Station.
Construction of the second phase instruments will begin once
the initial suite of seven instruments has been completed. We
anticipate that funding for this suite of instruments can be
secured for construction between 2009 and 2012. We are also
exploring ideas for the third phase of instruments for 2012-2015.
We will present proposals for new instruments with
opportunities for you to discuss the proposals and give your
views. You will also be able to hear about the status of the
Second Target Station Project and to visit the experimental hall
after the meeting to see progress at first hand.
Register to attend the event at http://ts-2.isis.rl.ac.uk/events/
Travel costs for UK participants will be reimbursed. We regret
that we are unable to reimburse travel costs for this meeting
for overseas participants.
The nearest railway station is Didcot Parkway and there are
frequent public transport connections to ISIS. If you require a
taxi to ISIS from the station, please contact the ISIS User
Office ([email protected]).
You can find information on how to travel to ISIS at
http://www.isis.rl.ac.uk/aboutIsis/directions.htm
1400-1700 CR12/13
Rutherford Appleton Laboratory
1230
Arrival and sandwich lunch
Chipir
Beam-line for atmospheric neutron research and testing
1400
Overviews
- Status of Second Target Station Project
- ISIS development plans including Phase
2 at Target Station 2
Exeed
Extreme sample environments diffractometer
Exess
Extreme sample environments spectrometer
Imat
Neutron imaging, materials science and engineering facility
1430
Phase 2 instruments for the Second Target
Station including discussion
Larmor
Multi-purpose instrument for small-angle scattering, diffraction
and spectroscopy
1600
Viewing of Target Station 2 experimental
hall with tea and mince pies
Lmx
Large molecule crystallography
Nessie
Time-of-flight spin-echo spectrometer
Meeting close
Zoom
High count-rate, focusing small angle scattering
1700
15
First Science and Technical Advisory
Committee July 2002
Complete R80 construction
March 2006
Detailed planning approval
March 2003
Complete target services area
structure January 2007
Approve initial instrument suite
June 2003
Begin extracted proton beam installation
in synchrotron February 2007
Approve target station design concept
July 2003
Complete extracted proton beam
September 2007
First Project Board
October 2003
Complete target services area
equipment December 2007
Complete earth moving and
landscaping November 2003
First proton beam to target area
December 2007
Complete access Road 10
October 2004
Begin instrument neutron guides
January 2008
Complete R78 technical support
building November 2004
Begin first phase instrument detectors
March 2008
Begin R80 experimental hall
construction January 2005
First measurable neutrons from target
March 2008
Compete R80 structural frame
May 2005
Begin instrument commissioning
April 2008
Complete target monolith foundation
September 2005
Target core fully operational
June 2008
R80 weather-tight
November 2005
Start of experimental programme
October 2008
ISIS is the world’s leading spallation neutron source, providing UK
and international researchers access to the best scientific facilities
of their kind. ISIS has contributed significantly to many of the
major breakthroughs in materials science, physics and chemistry
since it was commissioned in 1985.
Neutron scattering is a unique and powerful way of studying the
properties of materials at the atomic level. Neutron scattering
experiments reveal where atoms are and what they are doing,
enabling the material structure and information about the forces
between atoms to be measured.
Expansion of ISIS through the building of a second target station
was announced in April 2003 by the Science Minister Lord
Sainsbury as a key part of the UK investment strategy in major
facilities.
The ISIS Second Target Station will open up new opportunities in
technologically significant areas, particularly in the fields of soft
condensed matter, bio-molecular science, advanced materials and
nanoscale science. The experimental programme will begin in 2008.
Contact information
Project Sponsor
ISIS Director
Communications & Media
Robert McGreevy – [email protected]
Tel: +44 (0) 1235 445599
Andrew Taylor – [email protected]
Tel: +44 (0) 1235 446681
Martyn Bull – [email protected]
Tel: +44 (0) 1235 445805
Project Manager
Harry Jones – [email protected]
Tel: +44 (0) 1235 445182
Project Scientist
Jeff Penfold – [email protected]
Tel: +44 (0) 1235 445681
ISIS Pulsed Neutron & Muon Source
Science and Technology Facilities Council,
Rutherford Appleton Laboratory,
Harwell Science and Innovation Campus, Didcot OX11 0QX
United Kingdom
ts-2.isis.rl.ac.uk
ISSN 1751-3154 (Print)
ISSN 1751-3162 (Online)
Science & Technology