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LCLS. LCLS Commissioning Status P. Emma for The LCLS Commissioning Team LCLS FAC Meeting November 11, 2008. Machine Performance Estimated FEL Power Ultra-Short Pulse Possibilities Plans for 2009. Results published in FEL’08 and Linac’08 proceedings.
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LCLS LCLS Commissioning StatusP. Emma for The LCLS Commissioning TeamLCLS FAC MeetingNovember 11, 2008 • Machine Performance • Estimated FEL Power • Ultra-Short Pulse Possibilities • Plans for 2009 Results published in FEL’08 and Linac’08 proceedings
Phase-II Commissioning Highlights (2008) • Injector Commissioning: Apr-Aug, 2007 (DONE) • Phase-II Commissioning: Dec-Aug, 2008 (DONE) • Great drive-laser uptime (99%) and good performance • Projected emittances 0.7-1.6 mm at 0.25 nC, 10 GeV • Routine 30-Hz e- to 14 GeV (~24/7 with ~90% up-time) • Bunch compression fully demonstrated down to 1-2 µm • New cathode installed with greatly improved thermal emittance • 20-pC bunch with 0.14-µm emittance (and 2-fs length?) • Electron bunch appears bright enough to drive 1.5-Å FEL • Phase-III commissioning started Nov. 3, 2008 – X-rays by July ‘09
Design and Typical Measured Parameters (Aug. 2008) * horizontal slice emittance likely < 1 µm
Bunch Compression & CSR Measured after BC2 (0.25 nC) sz < 5 mm nominal sz 2 mm old screen used sz > 25 mm BC2 (4.3 GeV) TCAV (5.0 GeV) L2 BSY (14 GeV) 4 wires 550 m
g(exey)1/2 = 1.04 mm (3.3 days) May 24, 2008 00:01 to May 27 09:00 Emittance Near End of Linac Over Long Weekend long weekend run at 0.25 nC with no tuning
Beam Appears Bright Enough for FEL Saturation at 0.15 nm M. Xie method, with wakes FEL Power 3D Gain Length Calculation based on measured end-of-linac projected emittance values, measured peak current, and design undulator parameters (assuming undulator alignment and 0.01% rms slice energy spread – not yet measurable)
TAIL New Cathode: Time-sliced x-Emittance at Very Low Charge 0.14 µm (not same data) 20 pC, 135 MeV, 0.6-mm spot diameter, 400 µm rms bunch length (5 A)
sz 1 mm ? LiTrack (no CSR) 8 kA? Measurements and Simulations for 20-pC Bunch at 14 GeV Photo-diode signal on OTR after BC2 shows minimum compression at -34.5 degL2-linac phase. SIMULATED FEL PULSE Y. Ding 1.5 Å, 3.61011 photons Ipk = 4.8 kA ge 0.4 µm LCLS FEL simulation at 1.5 Å based on measured injector beam and Elegant trackingwith CSR at 20 pC. Horizontal projected emittance measured at 10 GeV, after BC2, using 4 wire-scanners.
120-Hz RF & Controls Testing Done(Gun, L0a, L0b, L1-S, & L1-X) • Measured 120-Hz “Timeslot” phase jitter for all injector RF stations: • Gun, L0a, L0b ~0.8 deg rms (tol. = 0.1 deg) • L1S ~0.17 deg rms (tol. = 0.1 deg) • L1X ~0.3 deg rms (tol. = 0.5 deg) • Observe ~1 deg difference on every 4th pulse (L0a, L0b, L1X) • Measurements confirmed with old SLC control system and new Beam Synchronous Acquisition system • More feedback development is needed (beam-based and RF-based) • Radiation measured are below posted limits at each klystron • Gun temperature and vacuum response OK at 120 Hz M. Stanek
The LCLS Laser Heater is Ready (except undulator) Beam through chicane already… Controls ready IR & e- beams on OTR screens now
Laser-Heater OTR screens (7) RF Gun YAG screens (7) Solenoid Wire scanners (7) Dipole magnets (8) L0a Beam stoppers (2) S-band RF acc. sections (5) Gun Spectrometer L0b Emittance Screens/Wires Emittance Screen/Wires RF Deflector L1S 2-km point in 3-km SLAC linac X-band RF acc. section BC1 135-MeV Spectrometer TD11 stopper 135 MeV 250 MeV RF Deflector (LOLA) + special lattice configuration in spectrometer allows fine measurement of time-sliced energy spread (to <6 keV) sE 6 keV rms (40 mm)
New emittance data at 135 MeV taken on Nov. 8, 2008 just 2 days into the turn-on gex = 0.61 µm q = 0.25 nC gey = 0.67 µm
Important Dates for 2008/2009 Commissioning • Nov. 3, 2008: Startup (establish beam to end of linac again) • Dec. 3, 2008: Install laser-heater undulator (?) • Dec. 15, 2008: First beam through LTU & to dump? • Dec. 19, 2008: SLAC shuts down for holidays • Jan. 5, 2009: Startup again (establish beam in LTU & dump) • March 2, 2009: Install ~25 undulators & PPS cert. (~2 wks) • May 14, 2009: First beam in FEE • July 2009: Photons in NEH • August 2009: Start AMO Experiment
LCLS Installation and Commissioning Time-Line InstallUndulators First Light in FEH PPS Cert. LTU/Dump LTU/Und Install X-Rays in NEH First Light in FEE CD-4 (7/31/2010) FEE/NEH Install FEH Hutch BO PEP-II run ends now J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J D M D A 2008 2009 2010 Down Down? PPS LTU/Und Comm. NEH Ops & Commissioning Linac/BC2 Commissioning Re-establish e- to SL2 FEL/FEE Commissioning Nov. 3, 2008
LTU/Undulator/FEE/FEL Commissioning H. Tompkins + heater