SLAC ILC Accelerator R&D Program

Transcription

1 SLAC ILC Accelerator R&D Program SLUO Meeting September 26 th, 2005 Tor Raubenheimer

2 SLAC 2005 ILC Program NLC group was redirected towards ILC Developed a program aimed at the topics identified in the 2003 Technical Review Committee report and at the 1 st ILC Workshop Description at: The 2003 TRC identified 1 R1 and 15 R2 R&D items DESY, Fermilab, and KEK are focused on the outstanding R1 and the R2 on the linac sub-unit test SLAC is focused on the other 14 of the 15 R2 items and is working with US labs, KEK, UK groups, and DESY SLAC used technical expertise to study paths for cost reduction High power rf (klystrons, couplers, circulators, and rf distribution) and solid state modulators Major participation at ILC Workshops (KEK and Snowmass)

3 Snowmass LC Meeting

4 SLAC 2006 ILC Program Program for FY06 has two main elements Development of the ILC RDR (Reference Design Report) Overall design: Beam parameters, Optics, Emittance preservation, Stability/alignment, Instrumentation, Availability, MPS, and Operational issues Electron & Positron sources and Damping rings Linac design and wakefields/cavity optimization Beam Delivery System and Interaction Region Conventional construction implications and site development Continuing R&D on linac rf technology for better cost & performance Modulators, rf distribution, and couplers Not (much) SC Cavity fabrication Worked with Barry Barish and Gerry Dugan to develop plan

5 Experimental Basis for the ILC Design SLC, FFTB, ASSET, E-158 Bunch Compression SLC and FEL s SLC and (ATF2 in the future) ε Preservation TESLA Test Facility (SMTF & STF in the future) Linac rf system BDS & IR ATF, 3 rd Gen Light Sources, SLC SLC, E-158 e+ / e- Sources Damping Rings

6 Accelerator Design (Reference Design Report) SLAC has a very strong accelerator design group Have thought about most aspects of the LC design and ops We have groups focused on most subsystems with the exception of the SC cavity fabrication Sources Damping rings Bunch compressor, prelinac collimation, and spin rotator Linac rf system and linac beamline Beam delivery system Collaboration building is another large part of our efforts Work on FNAL, ATF and KEK, DESY Coordination of BDS, MDI, instrumentation projects, LET, e+

7 L-Band RF System R&D SLAC has strong expertise in rf power generation and lots of experience from the X-band rf program to apply to ILC Goal: reduce cost of the rf system (which is roughly 15% of TPC in USLCTOS cost estimate) and improve performance (better reliability, higher efficiency, ) Working on solid state modulators, L-band klystrons, and other rf components Collaborating with Fermilab on three projects for the SMTF: Modulator switches Bayonet box for cryo-system Electron-beam welding of SC cavities Would like to do more couplers for example

8 Major Test Facilities End Station B Support Advanced Acceleration experiments (including X-band work) Create new L-band rf Test Facility Develop klystron and modulators for ILC Test normal conducting structures for e+/e- sources Construct coupler test facility Facilities also available in Klystron Test Lab End Station A Study Interaction Region issues and instrumentation Mockup of full IR ATF/ATF-2 (Located at KEK but with big SLAC participation) Test final focus system using very low emittance beam Work on the linac test facilities around the world: DESY, FNAL, and KEK

9 Electron and Positron Sources Electron source Continuing photocathode development Creating space to begin laser and gun development Need to start design simulations Positron source (program with LLNL) Studying target design for undulator, conventional, and Compton sources Radiation damage Thermal shock / beam damage Engineering issues (high rotation speed, remote handling) Capture and optics studies Normal conducting capture structure design and fabrication Complete E-166 polarized positron production (summer 2005)

10 Accelerator Structures (e+ and e- Sources) Need normal conducting structures for capture regions in the electron and positron sources Problems with rf heating and possibly beam loss Building ½ length standing-wave structure to be tested in End Station B facility with 5MW of rf power Fabrication started installation in spring

11 E-166: Polarized Positrons (June 2005 Run)

12 Damping Ring Aperture (Beam Dynamics Studies) New optics proposed based on PEP-II non-interleaved sextupole correction Pi-cell and FODO cell designs Dynamic aperture in Dogbone Damping Ring designs TME (DESY TDR) Pi-cell (low α Pep-II) FODO (high α Pep-II) Injected positron beam: ε x = ε y = 1x10-6 m-rad, tracked using LEGO with single-mode wigglers and multipole errors in the other magnets.

13 ATF Damping KEK (Low Emittance Source) Prototype electron damping ring with strong SLAC participation SLAC visits totaling 1 FTE last year Hardware and software projects BPM and other instrumentation Kicker magnets (fast kicker R&D and extraction kicker replacement) Beam-based alignment and ORM procedures (later used on PEP-II) Instability studies and Emittance tuning (lowest emittance source in world)

14 New ATF Extraction Kicker Refurbished SLC kickers for ATF Shipped July 05 for installation Oct ns long pulse to prep ATF for ILC-like beam extraction A

15 Fast Damping Ring Kickers (Damping Ring Design) High speed ring damping kicker developed by LLNL/SLAC 3kV with 5ns rise time and 10ns flat top Tested at the ATF damping ring

16 Secondary Electron Yield (Damping Ring Instabilities) Test chambers being constructed for installation in PEP-II in 2005/2006 Test different samples in real environment Test grooved chambers as a potential solution

17 Superconducting Linac Quad (Linac Beam Dynamics) Understand limitations of beam-based alignment techniques by measuring SC quadrupole Need to achieve ~25 um alignment Requires center motion of less than few um as excitation is varied SC Quad Constructed in Spain for DESY SLAC is building cryostat RF BPM Working with KEK and LCLS on rf bpm design Test integrated quad/bpm package in 2006

18 High Resolution BPMs Rf BPMs tested at ATF ~20 nm resolution measured Building electronics for ATF2 bpms HOM detectors tested at TTF 8 um resolution measured against TTF BPMs 16 um resolution comparing against other modes

19 TTF Cavity HOM Project (Linac Diagnostics) TTF HOM signals used for beam feedback stabilize FEL beam ACC4 Dipole signal versus time Building electronics for 40 more systems for TTF-2 Offset Use of HOM BPM signals for beam position offset nulling feedback Linda Hendrickson / Joe Frisch Pulse number

20 Beam Delivery System (System Design) Dual IR baseline design independent incoming & outgoing beamlines SC Quads from BNL The baseline for two IRs has greater flexibility: Independent incoming and outgoing beamlines, higher luminosity reach, flexibility in operation, upgradeability to γγ in 20mrad IR Better background & detector hermeticity (with less luminosity reach, poorer diagnostics & less operational flexibility) in 2mrad IR Two detectors in truly independent collider halls

21 Beam Delivery System (System Design) Single IR design concept In a single IR, do not have to separate incoming beamlines Crossing angle can be minimized to reduce backgrounds etc but still keep advantages of independent incoming and outgoing beamlines Limitation is due to incoming/outgoing magnet separation BNL 380mm QD0 Prototype Compact SC Final Quad compensating coil fringefield-free extraction aperture

22 ATF-2 at KEK ATF-2 would be the BDS test facility Follow-on to FFTB New FFS optics Operational issues Train next generation ILC like optics at ATF-2 New final focus

23 End Station A Test Facility For Prototypes of Beam Delivery and IR Components Collimator design, wakefields (T-480) Begin in November BPM energy spectrometer (T-474) Synch Stripe energy spectrometer (T-475) IP BPMs, kickers EMI (electro-magnetic interference) IR Mockup PAC05 paper/poster: SLAC-PUB-11180, e-print Archive: physics/ CCLRC LLNL QMUL U. of Bristol UMass Amherst CERN Lancaster U. SLAC UC Berkeley U. of Oregon DESY Manchester U. TU Darmstadt U. of Cambridge KEK Notre Dame U. of Birmingham UCL

24 End Station A: T-474 rf cavity BPMs at ASSET for E158 Initially, will use SLAC Linac BPMs. New electronics based on nanobpm work at KEK, being developed by UC Berkeley diameter rf cavity BPMs moved from SLAC Linac to End Station A rf cavity BPM New BPMs, optimized for energy spectrometer, to be designed at University College London and in collaboration with BPM experts at SLAC and KEK

25 Civil Design and Siting

26 Availability and Operations The ILC will be an order of magnitude more complex than any accelerator ever built If it is built like present HEP accelerators, it will be down an order of magnitude more (essentially always down) For reasonable uptime, component availability must be much better than ever before requires serious R&D Device Required MTBF Improvement Factor MTBF from Present Experience (khours) magnets - water cooled 20 1,000 power supply controllers flow switches water instrumention near pump power supplies kicker pulser coupler interlock sensors 5 1,000 collimators and beam stoppers all electronics modules AC breakers < 500 kw vacuum valve controllers regional MPS system 5 5 power supply - corrector vacuum valves 3 1,000 water pumps modulator 50 klystron - linac 40 coupler interlock electronics 1,000

27 L-Band RF System

28 Marx Generator Modulator High efficiency Marx Generator modulator being designed Modular system for lower cost and greater availability High voltage operation to simply design and linac tunnel Marx generator test area

29 Marx Generator Modulator

30 Klystrons (RF Power Generation) DESY 10 MW Klystron Program Three Thales tubes built, five more ordered two have meet full specs (but only run a few hundred hours) One CPI tube built achieved 10 MW at short pulse length, limited by CPI modulator may come to SLAC after testing at DESY One Toshiba tube built and under test 10 MW, 1 ms achieved SLAC Klystron Program Developing a 10 MW L-band Sheet-Beam Klystron (currently no funding) If multi-beam program falters, consider lower perveance, single beam, 5 MW tube, possibly with PPM focusing Buy commercial 5 MW tubes as needed for L-band program Possibly collaborate with DESY and CPI on 10 MW tube

31 L-band RF Station (End Station B) Begged, borrowed, or stole most components for a 5MW L-band rf station 1 st power in 3 months New 5MW klystron arriving next year we have one to start with

32 End Station B: ILC Program L-Band RF Test Facility Build two L-band test stations next to NLCTA in ESB Test modulators and klystrons Provide rf power for NC accelerator structures and couplers

33 Summary Broad program SLAC group is recognized as excellent throughout the world Strong design effort with beam dynamics studies, integrated R&D and engineering studies Experimental program is picking up speed NLCTA is operating; L-band rf station is being constructed in ESB End Station A program should be starting up soon Working at ATF and working on ATF-2 at KEK Working on TTF-2 at DESY Lots of projects coming to fruition in 2006 Lots to do! New people coming on board Contact us if interested in ILC!