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PAC-2001, Chicago, IL Paul Emma SLAC SLAC Issues and R&D Critical to the LCLS UCLA LLNL.

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Presentation on theme: "PAC-2001, Chicago, IL Paul Emma SLAC SLAC Issues and R&D Critical to the LCLS UCLA LLNL."— Presentation transcript:

1 PAC-2001, Chicago, IL Paul Emma SLAC SLAC Issues and R&D Critical to the LCLS UCLA LLNL

2 PAC-2001, Chicago, IL Linac Coherent Light Source (LCLS) 14.3-GeV electrons14.3-GeV electrons 1-  m emittance1-  m emittance 230-fsec FWHM pulse230-fsec FWHM pulse 2  10 33 peak brightness *2  10 33 peak brightness * 10 10 over 3 rd -gen. sources10 10 over 3 rd -gen. sources * photons/sec/mm 2 /mrad 2 /0.1%-BW add bunch compressors install 120-m undulator in ‘FFTB’ hall new RF-gun at 2-km point produce intense x-ray SASE radiation at 1.5 Å 4 th -Generation X-ray SASE FEL Based on SLAC Linac

3 PAC-2001, Chicago, IL Other FEL-based sources being tested, built, or planned…  Source Development Laboratory (SDL) at BNL-NSLS  Electron beam testing  VISA experiment at BNL-ATF  Saturation achieved, March 2001  FEL’s under study in Japan, Italy, England and Germany (BESSY II)  X-ray TESLA FEL at DESY (associated with linear collider)  TDR written  Harmonic Generation (HGHG) successful at BNL-ATF  Low Energy Undulator Test Line (LEUTL) at ANL-APS  High gain and saturation observed at 390 nm  TESLA Test Facility (TTF) at DESY  Lasing with gain ~3000 observed at 80-180 nm

4 PAC-2001, Chicago, IL  Design Study Report published 1998 (SLAC-R-521) led by Max Cornacchia  New LCLS project leader at SLAC is John Galayda (formerly of ANL/APS)  Critical Decision-0 (CD-0) approval was signed by DOE in June 2001 LCLS Project Update  Pre-engineering in 2003, construction in 2004, and operation in 2007  Published plan for first 5 experiments (femto-chemistry, atomic physics, warm dense matter, …), Sep. 2000

5 PAC-2001, Chicago, IL  Acceleration and Compression  Undulator  X-ray optics  Injector Requirements LCLS Issues and R&D    1  m at 1 nC and 100 A  Stability <1 psec timing & <2% charge   -preservation  ‘CSR’ and wakefields  RF stability of 0.1°, 0.1% rms  Design, precise fabrication, and thermal stability  Trajectory alignment to <5  m  Undulator wakefields

6 PAC-2001, Chicago, IL L  6 m R 56  36 mm L  24 m R 56  22 mm L  66 m R 56 = 0 L  120 m L  9 m  rf  38° L  330 m  rf  43° L  550 m  rf  10° Linac-0 L  6 m LCLS Acceleration and Compression undulator 150 MeV  z  0.83 mm    0.10 % 250 MeV  z  0.19 mm    1.8 % 4.54 GeV  z  0.022 mm    0.76 % 14.35 GeV  z  0.022 mm    0.02 % SLAC linac tunnel undulator hall...existing linac new Linac-3Lin-1Linac-2 BC1BC2 DL2 Linac-X L  0.6 m  rf =  X  Emittance control given coherent synchrotron radiation in bends  Adequate machine stability (RF, charge, bunch-timing, …) RFgun 2-km point in SLAC linac double chicane reduces CSR

7 PAC-2001, Chicago, IL 6D-Tracking using Parmela to 150 MeV and Elegant* to undulator, including:  Space charge (to 150 MeV)  Misalignments (RF, quads, BPMs)  2 nd -order optics  CSR and ISR  Long. And Trans. Wakefields  Resistive-wall wakefields  Steering  Emittance correction TRACKING energy profile energy-timetemporaltransverse * Elegant, by M. Borland 150 MeV 250 MeV 4.54 GeV 14.3 GeV 22  m 195  m 830  m 22  m 0.02%

8 PAC-2001, Chicago, IL Stability Studies Pulse-to-pulse ‘jitter’ estimates based on repeated tracking including parameter variations M. Borland, WPPH103 More studies including CSR and 6D tracking in… 22  3  m rms bunch length variation 0  109 fsec rms arrival time variation linac  phase  0.1 deg-S rmslinac  phase  0.1 deg-S rms linac  voltage  0.1% rmslinac  voltage  0.1% rms Gun timing jitter 0.9 psecGun timing jitter 0.9 psec Charge jitter 2% rmsCharge jitter 2% rms linac  phase  0.1 deg-S rmslinac  phase  0.1 deg-S rms linac  voltage  0.1% rmslinac  voltage  0.1% rms Gun timing jitter 0.9 psecGun timing jitter 0.9 psec Charge jitter 2% rmsCharge jitter 2% rms R. Akre, TPAH105 Track 100k macro-particles in long.-2D 2000 times with ‘jitter’…

9 PAC-2001, Chicago, IL Undulator Hall (FFTB) Install 122-m long planar undulator in existing FFTB hall Near hall Far hall UndulatorUndulator SLAC looking west Inside FFTB hall

10 PAC-2001, Chicago, IL QFQDBPM space for x- ray diagnostics undulator section 3.42 m Vanadium permendu r poles Nd-Fe-B magnets Undulator (ANL/APS) Beam Pipe: 5-mm ID 120-m Length undulator line length 122m undulator period, u 30mm undulator parameter, K 3.71 undulator section length 3.42m magnetic gap height 6.0mm No. of undulator sections 33 break length (short) 0.19m break length (long) 0.42m 1-  m BPM  cavity and button-type in compact package (G. Decker, ANL) E. Moog, TOPA012 Quad-magnets and undulator sections on independent movers eeee Planar hybrid type vacuum pump

11 PAC-2001, Chicago, IL Titanium strong- back Va permendur poles Nd-Fe-B magnets Courtesy E. Gluskin, ANL LCLS 9-Pole Prototype Undulator (ANL) E. Moog, TOPA012 Al temperature- compensation plate 3.4-m section is under construction at ANL

12 PAC-2001, Chicago, IL Radiation damage interferes with atomic positions and the atomic scattering factors Janos Hajdu Motivation for even shorter x-ray pulses  t /fsec Further e  compression difficult:  CSR in bends  Undulator wakefields Coulomb Explosion of Lysozyme (50 fs) Compress x-ray pulse with chirp & slicer (R. Bionta, LLNL) …or… …or…

13 PAC-2001, Chicago, IL Two-stage undulator for shorter pulse 52 m 43 m eeee 30 m SASE gain (P sat /10 3 ) SASE Saturation (23 GW) Si monochromator (T = 40%) time Energy C. Schroeder, WPPH121 time Energy  E FW /E = 1.0% time  t FW = 230 fsec x-ray pulse 1.0  10  4 time  t FW < 10 fsec Mitigates e  energy jitter and undulator wakes Also a DESY scheme which emphasizes line-width reduction (B. Faatz) UCLA

14 PAC-2001, Chicago, IL New proposal for:  LCLS accelerator and x-ray optics R&D  Ultra-short x-ray science program at SLAC 28 GeV Add 12-meter chicane compressor in linac at 1/3-point (9 GeV) Damping Ring (   30  m) 9 ps 0.4 ps 80 fs 50 ps SLAC Linac 1 GeV 20-50 GeV FFTB RTL 30 kA 80 fsec FWHM 1.5% Short Bunch Generation in the SLAC Linac Compress to 80 fsec in 3 stages Existing bends compress to <100 fsec ~1 Å 10-m undulator P. Emma, P. Emma, FPAH165 Add to understanding of CSR and X-ray optics

15 PAC-2001, Chicago, IL  Emittance generation and preservation Summary of Key Issues  Stable operation  Undulator errors and trajectory control  Gun   1  m, repeatable at 120 Hz  Need better understanding of CSR  RF, laser, and feedback systems  Fabrication, alignment, and BPMs  Wakefields  SASE saturation at ~1Å


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