101006 BES RD Discussion Raubenheimer - SLAC Portal

Role of Accelerator Physics R&D
in Facility Operations
Tor Raubenheimer
Discussion on the Integration of Accelerator Physics
R&D and Operations
October 6 th , 2010

Introduction
• Source brightness has been increasing 1000x every decade
• Future challenges to understand dynamics and time evolution
• Requires improved coherence and energy bandwidth
– Short pulses and high brightness electron sources
– Seeding of soft and hard x-ray FELs
– Multiple pulses with timing control for pump probe
• Meeting these challenges will require advances in both
fundamental accelerator concepts as well as directed
development of accelerator science and technology
• Program will need a combination of quasi-parasitic use of
operating facilities and a diverse set of dedicated test beds
Role of Accelerator Physics R&D
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Why Experimental Accelerator R&D?
• Advancement of BES science will benefit from
advancement of accelerators and detectors
• Accelerator research requires parallel advancement of
beam theory and experiment
– Many concepts require experimental study because they are either
too complex to fully model or because the risk of failure is too high
(for example a critical technology in a user facility)
– Other concepts are only uncovered experimentally
• Accelerator facilities are expensive and heavily subscribed
– Some experimental R&D can be best performed with high quality
user beam
– Other R&D needs special requirements or significant time making
inefficient use of user facilities
Role of Accelerator Physics R&D
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Examples of R&D at Operating Facilities
• Understand COTR and
microbunching in LCLS
• Use of a slotted foil to make
short bunches at LCLS
• Beam loss in H- linac at SNS
– Expected no loss in the SC linac
– Investigate IBS as possible mechanism
– Not presently a limitation but could be
at higher beam power

Accelerator R&D and Facility Operations
• Accelerator R&D is expensive
– Requires complicated hardware and extensive support staff making
it hard to support R&D as a stand alone program
• Some R&D can be done at an operating user facility
parasitically or during MD time
• In other cases, user facilities can provide necessary
hardware and/or infrastructure while the R&D programs
cover incremental costs
– Examples: GTF and SPPS
• Another approach is to share costs across OS programs
– Most R&D programs benefit from week-on/week-off type schedules
but facilities like to run more continuously share facilities
Role of Accelerator Physics R&D
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Need for Accelerator R&D Test Beds
• Operating user facilities will enable some R&D, especially
that which is directed toward the program
• Other R&D requires more time or hardware modification
than available at an operating user facility
• Examples:
– Demonstration of SASE at short wavelengths: UCLA, ATF, TTF, …
– SPPS at SLAC studied many of the short bunch issues pre-LCLS
– Concept of emittance exchange was demonstrated at A0 at FNAL
– CSR e was measured at CTF-II, then SPPS and then the LCLS
– Echo-7 experiment is demonstrating a soft x-ray seeding technique
– Need additional understanding of CSR, microbunching and COTR
for future high brightness injectors
Role of Accelerator Physics R&D
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Some Existing Accelerator
R&D Test Beds
• ATF and SDL @ BNL
• CESRTA @ Cornell
• Duke Storage Ring @ Duke
• AWA @ ANL
• Neptune @ UCLA
• NLCTA and ASTA @ SLAC
• BELLA and FACET @ LBNL
and SLAC
• ATF and ATF2 @ KEK
• SCSS @ Spring-8
• TTF / FLASH @ DESY
• EMMA and ALICE @ Daresbury
• CTF-III @ CERN
• Some of these facilities have been
aimed at specific R&D programs
while some have supported broad
R&D programs
• Test beds enable detailed study of
fundamental accelerator processes
and technology as well as the
opportunity for accelerator
education
• Approximate breadth of programs
~ directed program
~ broad-based (acc. user) program
~ mixed program
New Acceleration Techniques
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Example: NLC Test Accelerator RF Testing,
Laser Acceleration and Beam Dynamics
• Test facility supports 3 experimental programs: rf development, direct
laser acceleration and Echo-7 FEL seeding experiment
– L-band, S-band, and X-band rf sources, 3 laser systems and rf gun e- source
– Synergies between programs has enabled rapid progress on R&D programs
– Upgrades of systems benefit all programs
Echo-7 Experiment at NLCTA
Role of Accelerator Physics R&D
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Summary
• Many critical R&D topics can be directly pursued at
operating user facilities in a quasi-parasitic mode
• Dedicated test facilities are required to support other critical
R&D (and provide a training ground for students)
• Use of operating accelerators as well as dedicated test
facilities is essential to advance the frontiers of accelerator
science and technology
– Operating user facilities can enable operation of dedicated test beds
without impacting the primary program
• Important to maintain diverse set of dedicated test facilities
as well as dedicated time at user facilities to enable next
generation of light sources
Role of Accelerator Physics R&D
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