Transcript Document

Accelerator Systems Division
FACET Accelerator Overview
John Seeman for the FACET Study Group
PPA Directorate
Stanford Linear Accelerator Center
DOE FACET Review
February 19-20, 2008
Accelerator Systems Division
Topics
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FACET accelerator overview
Brief look at science program
Changes since the SABER review of Dec 2006
Brief budget overview
Accelerator Systems Division
FACET Accelerator Team
• Management: R. Erickson, S. Kahn, J. Jaros, D.
MacFarlane, T. Raubenheimer, J. Seeman
• Mechanical engineers: L. Bentson, D. Blankenship, S.
DeBarger, N. Li, H. Shin
• Area Manager: A. Baker, T. Graul
• Optics: Y. Nosochkov, M. Woodley, T. Fieguth
• Alignment: C. LeCocq
• Beam dynamics: K. Bane, P. Emma
• Radiation physics: J. Bauer, A. Prinz
• Personnel Protection System: P. Bong, K. Turner
• Experimental region: M. Hogan, D. Walz, M. Woods, C.
Hast
• Physics consultants: R. Iverson, P. Krejcik
Accelerator Systems Division
Overview
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There was a constant demand for electron and positron beams in the Final Focus Test
beam (FFTB) and End Station A (ESA) from a wide variety of accelerator physics users.
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However, the FFTB has been removed to make room for the Linac Coherent Light Source
(LCLS). ESA is still in use.
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Many locations at SLAC have been studied for FACET. The optimum location is Linac
Sector 20 for the Accelerator Science Facility (ASF) where the FFTB accelerator beam
capabilities (final focus) can be relocated in a straight forward fashion.
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FACET makes use of the PEP-II HER bypass line to take a damped e- beam to End
Station A, independent of LCLS.
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The existing electron longitudinal bunch compressor at the 1/3 point in the linac can be
modified to compress positron bunches, as well, opening new worldwide unique
opportunities for accelerator research.
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A Hadron Production Facility (for single particles) can be added to the A-Line to ESA.
Accelerator Systems Division
FACET Layout
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Hadron Production Facility
FACET has four areas:
Accelerator Science Facility (ASF) (Sector 20)
e+ bunch compressor (Sector 10)
Electron Bypass Line (EBL) extension to ESA
Hadron Production Facility in A-Line to ESA
Accelerator Systems Division
Basic FACET areas
• Final Focus (ASF) in Sector 20: Makes a small beam spot (<10
microns) for experimenters. Similar design and layout as FFTB final
focus.
• Sector 10 compressor for e+: Allows the production of positrons by eand the delivery of short bunch length e+ to the experimenter. Same
design and layout as present e- compressor.
• Bypass line (EBL): Allows independent operation from LCLS. Use
PEP-II HER injection bypass lines with 9 to 12 GeV e- with extension
built to join to A-line transport to ESA.
•  The technology is the same as the former FFTB, SLC arcs, and
existing PEP-II injection bypass lines. Many components salvaged
from SLC, FFTB, and PEP-II.
•  Minimal design and engineering needed!
Accelerator Systems Division
Proposed Construction Timeline
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Fall 2008: Installation of shielding wall in linac tunnel between Sectors 20 and
21. This allows tunnel installation work to proceed in Sector 20 while the
LCLS injector and other downstream systems operate in 2009.
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January through September 2009: Installation of Sector 20 magnets and
vacuum systems while LCLS commissioning activities proceed in downstream
sectors.
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Fall 2009: Removal of existing components of the PEP-II injection transport
systems in the BSY, as needed for FACET EBL. Modifications will be done to
the common line vacuum system in the BSY.
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FY 2010: First operation of Sector 20 ASF final focus with electrons.
Installation of positron compressor system in Sector 10.
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Fall 2010: Installation of the bypass line in the BSY and Hadron Production
Facility.
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FY 2011: All FACET systems fully operational, independent of LCLS
operations.
Accelerator Systems Division
Basic FACET ASF Beam Parameters
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Beam Energy = 30 GeV
Single bunch per pulse
30 Hz (120 Hz possible)
Charge per bunch (e- or e+) = 1 x 109 to 3.5 x 1010
Bunch length = 15-30 microns
Transverse spot size at experiment <10 microns
Energy spread = 0.5 to 4 % (full width)
Accelerator Systems Division
Sector 20 Final Focus
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Accelerator Systems Division
FACET Sector 20 Area
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e-
e+ target
Accelerator Systems Division
LCLS Injector (Sector 21)
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New FACET Wall
Accelerator Systems Division
Linac Housing: Site of ASF
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Accelerator Systems Division
Linac Tunnel
• ASF has a bunch compression
dog-leg beam line and a final
focus for the experiment.
• Longitudinal space for
experiments will be the same as
the FFTB.
• Transverse space is adequate
for accelerator experiments and
many detector experiments.
• Electric carts can travel in the
linac tunnel aisle now and will
be able to after the ASF and
experiments are installed.
Water
header
HER
LER
Bypass Bypass
LINAC
FACET / ASF
120 inches
LIGHT
PIPE
66 inches
132 inches
Tunnel
penetration
Water
header
e
e
bypass bypass
line
line
Plasma wakefield experiment
at focal point
Optical table
120 inches
Alignment
light pipe
66 inches
~2 meters
(~6.5ft)
132 inches
Accelerator Systems Division
Many places for User Counting Houses
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Accelerator Systems Division
Basic FACET EBL-ESA Beam Parameters
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Beam Energy = 9-12 GeV using PEP-II HER line
Single bunch per pulse
30 Hz (120 Hz possible)
Charge per bunch = 1 x 109 to 3.5 x 1010
Bunch length = ~1 mm
Transverse spot size at experiment < 1mm
Energy spread = <1 %
Accelerator Systems Division
Extension of HER Line to A-Line
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Accelerator Systems Division
Plasma Wakefield Acceleration Studies (ASF)
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Electron acceleration
Positron acceleration
Drive witness beam tests
Beam emittance
preservation
Accelerator Systems Division
Dielectric Wakefield Accelerators (ASF)
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Acceleration (e- and e+)
CSR studies
Coating optimization
Beam propagation tests
Theory/simulation cross checks
• Channel diameter optimization
Accelerator Systems Division
Detector Development (ESA)
• Development of beamline
instrumentation for ILC or other
applications
– New position monitors
– Precise beam energy measurements
– Collimator wakefield studies
• Detector development for ILC,
LHC and many other applications
– Proof-of-principle for new detectors
– Detector characterization and
calibration
– EMI & radiation damage studies
– Gas/air fluorescence for particle
astrophysics experiments
Accelerator Systems Division
Material Science (ASF and ESA)
• Pulsed magnetic fields
• THz radiation
• Photon detector
development
• Electronic structure of
metals
• Ferroelectric switching
Accelerator Systems Division
Old Proposal:
SLAC Overview with SABER in SLC South Arc
SABER consists of three main components:
•(1) Experimental area with final focus and beam dump in SLC South Arc tunnel.
•(2) Linac Pulse Compressor upgrade to compress positron bunches.
•(3) Bypass Line to deliver e- or e+ beams to SABER, bypassing the LCLS.
(2)
e+
e(3)
(1)
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Accelerator Systems Division
Old SABER: Reuse 1 km of PEP-II Injection Bypass Line
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Sector 20 (exists)
Linac Sector 21-30 (exists)
51 Line (exists)
Extraction
Line (new)
Drift Line
(exists but 12  30 GeV)
~50 m
~1000 m
South Arc
(exists)
Re-injection
Line (new)
~50 m
Drift Line:
Reuse: Vacuum chambers, pumps and controls
Beam position monitors
Beam size monitors
Steering corrector magnets
Quadrupole magnets and power supplies
New:
Extra quadrupole magnets, power supplies, supports, water
Accelerator Systems Division
Suggestions from SABER Review
• FACET team has answered the committee
recommendations from the DOE “SABER”
review held December 6-7, 2006:
• Broader science program:
– Added ESA beam for detector and accelerator studies.
– Added hadron production facility for single particle
detector studies.
• New location and lowest cost:
– Final focus in Sector 20 saves bypass line upgrade costs
and has easier beam tuning. (Saves 3.6 M$)
– ASF and ESA can operate simultaneously, independent
of LCLS.
• Manage the construction as a project:
– Project management team is now proposed.
Accelerator Systems Division
Budget changes from SABER  FACET (FY2007$)
• SABER budget total: 12.4 M$
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South Arc final focus: 2.4 M$
Linac bypass line (30 GeV) upgrade: 8.3 M$
Positron Bunch Compressor: 1.5 M$
Personnel Protection System upgrade: 0.2 M$
• FACET budget total: 15.5 M$
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Sector 20 ASF final focus: 7.1 M$
Positron bunch compressor: 1.5 M$
EBL Bypass line extension to ESA (12 GeV): 4.3 M$
ESA Hadron Production Facility: 0.6 M$
Project management: 2.0 M$
• Operations costs: ~6 M$ for 4 months for running
both ASF and ESA together.
Accelerator Systems Division
Conclusions
• FACET (ASF and ESA) is a solid advance over the old
design.
• The breath of the experimental program has been
significantly expanded.
• There are four components to the facility allowing staging
of the program.
• FACET construction matches the LCLS staff ramp down
plan and accelerator operations schedule.
• Budget estimates have been carefully managed to be as
low as possible.