Paul Emma, et al. LCLS FAC May 13, LCLS Commissioning: Results & Plans P. Emma, for the LCLS Commissioning Team LCLS FAC Meeting June 16, 2008 LCLS Phys. Rev. publication:

Paul Emma, et al. LCLS FAC May 13, LCLS Accelerator Layout SLAC linac tunnel research yard Linac-0 L =6 m Linac-1 L  9 m  rf   25° Linac-2 L  330 m  rf   41° Linac-3 L  550 m  rf  0° BC1 L  6 m R 56   39 mm BC2 L  22 m R 56   25 mm DL2 L =275 m R 56  0 DL1 L  12 m R 56  0 undulator L =130 m 6 MeV  z  0.83 mm    0.05 % 135 MeV  z  0.83 mm    0.10 % 250 MeV  z  0.19 mm    1.6 % 4.30 GeV  z  mm    0.71 % 13.6 GeV  z  mm    0.01 % Linac-X L =0.6 m  rf =  21-1 b,c,d...existing linac L0-a,b rfgun 21-3b24-6d X 25-1a30-8c Injector Commissioned (‘07) Commissioned in Jan beam parked here

Paul Emma, et al. LCLS FAC May 13, OTR screens (7) YAG screens (7) Wire scanners (7) Dipole magnets (8) Beam stoppers (2) S-band RF acc. sections (5) RF Gun Solenoid GunSpectrometer RFDeflector X-band RF acc. section BC1 L1S L0a L0b 2-km point in 3-km SLAC linac LCLS Injector Layout 135-MeVSpectrometer EmittanceScreens/Wires EmittanceScreen/Wires 135 MeV 6 MeV 250 MeV TD11stopper Commissioned in ‘07

Paul Emma, et al. LCLS FAC May 13, LCLS BC2 Area Layout (sector 24/25) OTR screens (3) Dipole magnets (4) S-band RF acc. sections 4.3 GeV (not to scale) BC2 OTR21 OTR22(25-3d) OTR_TCAV(25-9) BXKIK Kicker magnet (1) TCAV3(25-2d) 4 wire-scanners “de-scoped” Transverse RF deflector (1) 4 wire-scanners in sec-28 (300 m downstream) PH03 BPMS21 Phase monitor cavity (1) CE21 Collimator jaws (2 New installation in fall ‘07

Paul Emma, et al. LCLS FAC May 13, Commissioning Highlights Injector commissioning: April through August, 2007 (DONE) Phase-II commissioning: Dec.  Complete 3/31/08 (BC2 + Linac) Up to 1 nC of bunch charge available (mostly 0.25 & 0.5 nC used) Great laser uptime (99%) and good performance (again) Emittances  1  m after BC1 at 1 nC, 250 MeV (fairly routine) Routine e  to 14 GeV (24/7 except Wed. - ~90% up-time) BC1 dipoles & chicane motion fixed! No emittance growth in X-band RF cavity when best steered BC2 compression demonstrated (no dipole field quality issues) CSR effects measured in BC1 & BC2 – agree with codes so far Many beam (8) & RF (8) feedback systems running well Tested energy switching: 14, 10, 7.0, 4.3 GeV (<5 min. switch) Coherent OTR observed – compromises nearly all screens Gun RF probes changed in April ’08 (allows 120-Hz)

Paul Emma, et al. LCLS FAC May 13, Design and Typical Measured Parameters

Paul Emma, et al. LCLS FAC May 13, “Problems/Issues” from July ‘07 DOE Review Gun Faraday cup broken Gun toroid shorted during installation Some YAG screens not installed properly BC1 motion control limited (300 mm  260 mm) Cathode QE about 5-times lower than design Some controls tools late (orbit displays, fitting, magnet control & alarms) MCOR power supply ADC readback noise (fixed) Laser phase drift and lock trouble until mid-June ALL FIXED

Paul Emma, et al. LCLS FAC May 13, Laser Spatial and Temporal Shaping Temporal shape (6.6 ps FWHM) Spatial shape on cathode using iris S. Gilevich, G. Hays, P. Hering, A. Miahnahri, W. White 99% Drive Laser up time! 7.2 ps R = 1.4 mm ps 2008

Paul Emma, et al. LCLS FAC May 13, Quickly minimize emittance by scanning any parameter H. Loos Watch profiles as scan proceeds Powerful Scanning/Correlation Application

Paul Emma, et al. LCLS FAC May 13, Projected Emittance <1.2 μm at 1 nC (135 MeV)  x = 1.07 μm  y = 1.11 μm meetsinjectorgoals  = 60 μm

Paul Emma, et al. LCLS FAC May 13, Injector Emittance Measured Over 3 Days (0.25 nC)  x  y OTR screen at 135 MeV wire-scanner at 250 MeV after BC1  x  = 0.91,  y  = 1.01  x  = 0.83,  y  = 0.83 J. Welch injector is stable

Paul Emma, et al. LCLS FAC May 13, Laser & Electron-Based Feedback Systems L0 gun L3L2 X DL1BC1 DL2 L1 z1z1z1z1 1111 1111 V1V1V1V1 z2z2z2z2 2222 2222 V2V2V2V2 3333 V3V3V3V3 0000 V0V0V0V0 D. Fairley J. Wu J. Frisch Longitudinal Loops: DL1 energy BC1 energy BC1 bunch length BC2 energy BC2 bunch length Final energy (old loop) BC2 Laser Transverse Loops: Laser spot on cathode (2) Gun launch angle Injector trajectory X-band cavity position Linac trajectory (2 old) Undulator traj. (future) nowrunning BPMs CSR detectors Steering Loop (bunch length feedback still needs work)

Paul Emma, et al. LCLS FAC May 13, Bunch Length & Energy Feedback Systems Q = 0.25 nC  Q 2  1/2 /Q = 1.5% bunchcharge DL1 energy BC1 energy BC2 energy DL2 energy BC2 peak current BC1 peak current 216 ± 12 A 2170 ± 217 A 0.09% rms 0.03% rms 0.05% rms 0.03% rms Charge feedback:

Paul Emma, et al. LCLS FAC May 13, BC1 Dipole Field Quality Fixed Aug. ‘07 Nov. ‘07 Sext.tolerance J. Welch, S. DeBarger, N. Li, et al. ±3  beam fixed Poles were milled off and wider poles were bolted on and then the fields were shimmed.

Paul Emma, et al. LCLS FAC May 13, BC2 Dipole Field Quality OK No measurable quad field and sextupole is just at tolerance ±3  beam Beam energy scans confirm BC2 dipole field quality meets requirements OK

Paul Emma, et al. LCLS FAC May 13, Operating Point Summary Display H.-D. Nuhn Shows operators the main machine parameter targets and their present settings & includes save/restore files

Paul Emma, et al. LCLS FAC May 13, BPM-Measured CSR Energy Loss in BC1 at 0.25 nC (compares well with tracking) BPM Chicane Bend Y. Ding, Z. Huang A Phase shift of  0.4 deg is added to the Elegant curves CSR energy loss after BC1 measured with BPM Bunch length after BC1 measured with transverse RF Elegant BC2OFFBSY (14 GeV) TCAV (5.0 GeV) BC1 (250 MeV) L1SBPM operatingpoint  eeee

Paul Emma, et al. LCLS FAC May 13, Now plot horizontal emittance after BC1  º  x = 38  m  x = 55  m  º  x = 246  m  º Hor. CSR Emittance Growth after BC1 (250 MeV, 0.25 nC) ElegantMeas-1Meas-2ElegantMeas-1Meas-2 Horizontal emittance after BC1 vs. RF phase Vertical emittance after BC1 is almost unaffected Y. Ding, Z. Huang Elegant Data also exists at 1 nC and BC2 data (0.25 nC) also shows decent results Elegant operatingpoint

Paul Emma, et al. LCLS FAC May 13, RF Phase and Amplitude Stability (e.g., L0a) 0.05º rms (<0.07º) 0.05% rms (<0.07%) 20-second sample at 10 Hz New inj. RF systems meet jitter tolerances R. Akre, D. Kotturi, J. Craft, V. Pacak, et al. RF Feedback Running

Paul Emma, et al. LCLS FAC May 13, Normalized phase space centroid jitter after BC1 (~4% of rms beam size) D. Ratner Stability is not so far off of our goals (~10%) … near end of linac (~12% of rms beam size, but sometimes larger) Thanks to Controls group for new BPM electronics! RMS A xN = 14% RMS A yN = 9%  E/E jitter  0.03%  Q/Q jitter  1.5% RMS A xN = 3.9% RMS A yN = 3.4% 1-  beam size Q = 0.25 nC

Paul Emma, et al. LCLS FAC May 13, BC2 Chicane in the Linac at 4.3 GeV Chicane length 24 m, 4.3 GeV, 2º bends BobFuller

Paul Emma, et al. LCLS FAC May 13, Bunch Compression Measured after BC2 (0.25 nC)  z > 25  m BC2 (4.3 GeV) BSY (14 GeV) TCAV (5.0 GeV) 550 m  z < 10  m old screen used – poor res. Bunch length after BC2 measured with transverse RF  2 º shift applied to simulation  z  10  m L2 resolution limit

Paul Emma, et al. LCLS FAC May 13, Bunch is Over-Compressed L2 phase =  41 deg Chirp knob =  450 MeV Bunch is Under-Compressed L2 phase =  41 deg Chirp knob =  450 MeV Longitudinal Phase Space at 14 GeV older screen has poor resolution Vertical scale only approx. LiTracksimulation LiTracksimulation PR55 PR55 measurement measurement Transverse RF is ON Q = 1 nC

Paul Emma, et al. LCLS FAC May 13,  y = 0.9  m Q = 0.25 nC  y = 0.9  m Q = 0.25 nC Emittance measured 300 m after BC2 at 10 GeV with 10  m bunch length Emittance Measurements at End of Linac Using Wire Scanners  x = 76  m  x = 38  m  x = 49  m  x = 47  m wire scans Results still variable – requires careful work F.-J. Decker R. Iverson

Paul Emma, et al. LCLS FAC May 13, (3.3 days) May 24, :01 to May 27 09:00 weekend run at 0.25 nC, with no tuning Emittance Near End of Linac Over Long Weekend  (  x  y ) 1/2 = 1.04  m Saturates at 1.5 Å in 100 m (assuming BBA, etc)

Paul Emma, et al. LCLS FAC May 13, Now measure BPM jitter both with transverse RF OFF, and then ON (at constant phase)  t  ±0.6 ps slope =  2.34 mm/deg 9  m rms 110  m rms TCAV ON TCAV OFF BPM Y Position (mm) Measuring Bunch Arrival Time Jitter eeee V(t)V(t)V(t)V(t) S-band (2856 MHz) BPM Timing Jitter (w.r.t. RF) = (110  m)/(2.34 mm/deg) = deg  46 fsec rms Q = 0.25 nC

Paul Emma, et al. LCLS FAC May 13, LCLS Installation and Commissioning Time-Line LTU/Und/Dump Install Re-commission Inj/BC2 to SL2 LTU/UndComm. First Light in FEE PEP-II run ends FEE/NEH Install PPS Cert. LTU/Dump FEH Install CD-4 (7/31/2010) X-Rays in NEH First Light in FEH NEH Operations/ Commissioning JJFFMMAAMMJJJJAASSDDJJFFMMAAMMJJJJAASSOONNDDJJFFMMAAMMJJJJ ON A A Down PPS A A M M now Linac/BC2 Commissioning FEEComm. May 2, 2008 FEH Hutch BO Und. Seg. Install

Paul Emma, et al. LCLS FAC May 13, LTU/Undulator/FEE/FEL Commissioning See break-out presentations: LTU & Undulator Commissioning Plans (H.-D. Nuhn) FEL/FEE Overview Commissioning Plans (H. Tompkins) FEE Diagnostics & Commissioning (R. Bionta) See break-out presentations: LTU & Undulator Commissioning Plans (H.-D. Nuhn) FEL/FEE Overview Commissioning Plans (H. Tompkins) FEE Diagnostics & Commissioning (R. Bionta) H. Tompkins

Paul Emma, et al. LCLS FAC May 13, Problems/Issues End-of-linac x-emittance difficult to minimize and maintain, especially at 1 nC (CSR + micro-bunching?) Some wire-scanner vibration issues (~fixed in April ‘08) Most OTR screens are unusable due to COTR (laser heater should solve this in FY2009) Most linac BPMs need upgrade – 22 of 83 done with great resolution improvement (50  5  m - more on AIP List) BC2 bunch length monitor noisy or real jitter – (need beam synchronous acquisition for RF & BPMs or  -bunching?) RF phase jumps/drifts not uncommon – sometimes beyond feedback control range

Paul Emma, et al. LCLS FAC May 13, Summary Drive laser very reliable – performs well (great team) Injector in very good shape – runs well after setup Many measurements made – getting to know machine Emittances at end of linac difficult to tune, but nice results are possible with effort (  y is done!) Very encouraging results: e  beam supports 1.5-Å SASE We look forward to next phase (LTU, undulator, FEL, …) – preparations have begun (plans, software, checkout, …) Thanks to dedicated Commissioning Team + Controls, RF, Engineering, Operations, ASD, Maintenance, etc

Paul Emma, et al. LCLS FAC May 13, DONE

Paul Emma, et al. LCLS FAC May 13, BC2 Emittance Growth vs. Peak Current Q = 0.5 nC  x near end of linac (µm) BC2 Peak Current Feedback Set-Point (A)

Paul Emma, et al. LCLS FAC May 13, COTR After BC2 OTR screen just after BC2 with BC2 screen inserted (smoothes  -bunching) with BC2 screen OUT (  -bunching present – COTR!) OTR22OTR22

Paul Emma, et al. LCLS FAC May 13,  -Bunching in BC2 May Blow up X-Emittance OTR screen in BC2 OTR21  x,y measured with wire-scanners 320-m downbeam of BC2  x  y

Paul Emma, et al. LCLS FAC May 13, FY2009 Commissioning Activities Pre-Beam Checkout (Nov-Dec ‘08) – check-list in prep. Re-establish injector & linac beam quality (Nov-Dec ‘08) – have experience First LTU Commissioning with beam (Jan-Mar ‘09) – lots of time ‘Undulator’/Dump Comm. without undulators (Jan-Mar ‘09) Calibrate & commission: RF BPMs, Loss Monitors, BFWs, ADS BBA algorithm testing (without segments) Install undulator segments (Mar ’09, two wks) – optimize linac again First Undulator Segments Commissioning (Mar-Apr ‘09) Care with first transport to minimize radiation on segments Full alignment process (BBA, BFW’s) Commission FEE Diagnostics (Apr-Jun ‘09) Direct Imager, Calorimeter, Slit, Solid Attenuator, Gas Attenuator, Gas Detector Beam-Based K Measurement Components Optimization & characterization of SASE (Jun-Jul ‘09) Optimize linac beam quality (adjust compression, emittance tuning, BBA) Measure gain length