1. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Injector Commissioning Plans C.Limborg-Deprey Gun exit measurements Thermal emittance Energy, Energy Spread … 135 MeV measurements Slice, projected emittance Energy spread (abs., corr. and uncorr.) Bunch length Alternate tunings Low charge  critical for good modeling critical for good emittance compensation   slice < 1  m,  proj. < 1.2  m  I peak = 100 A  commissioning of other systems requireme at least  0.2 nC, 3ps pulse,  proj. < 2  m

2. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Gun S1S2 L0-1 19.8MV/m L0-2 24 MV/m ‘Laser Heater’ ‘RF Deflecting cavity’ TCAV1 3 screen emittance measurement 6 MeV  = 1.6  m  ,un. = 3keV 63 MeV  = 1.08  m  ,un. = 3keV 135 MeV  = 1.07  m  ,un. = 3keV DL1 135 MeV  = 1.07  m  ,un. = 40keV Spectrometer Linac tunnel UV Laser 200  J,  = 255 nm, 10ps, r = 1.2 mm Spectrometer

3. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 ‘Laser Heater’ ‘RF Deflecting cavity’ TCAV1 3 screen emittance measurement Gun Spectrometer Linac tunnel Straight Ahead Spectrometer Thermal emittance + Uniformity 1243

4. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Emission Cathode imaging Point-to-Point Imaging Transverse uniformity of emission disk Ellipticity + Slope of Edges Thermal emittance measurement Infinite-to-Point imaging Divergence at cathode Model thermal emittance Good thermal emittance model is fundamental for experiment/simulations

5. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Above: Laser cathode image of air force mask in laser room. Below: Resulting electron beam at pop 2. Above: Laser cathode image with mask removed showing smooth profile. Below: Resulting electron beam showing hot spot of emission. Laser masking of cathode image at DUVFEL Courtesy W.Graves

6. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Thermal emittance At YAG2 With low accelerating gradient Good resolution (better than at YAG1) YAG2 == Image of divergence of source Assumes  th = 0.6 mm.mrad

7. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Imaging source divergence what type of momentum distribution?

8. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Calibrations, Orthogonality of knobs Rotation of cathode image Gun Energy Steering coil, offset at YAG1/YAG2 Spectrometer Shottky scan (for short bunch ~2ps) RF Phase Shottky scan at different gun fields Energy spread at low/high current in spectrometer Gun BalanceOffset in solenoid scan curve Direct field measurement from probes Solenoid Scan beam size compared at YAG1 / YAG2 Waist vs charge

9. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Calibrations

10. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Schottky Scan J.Schmerge, GTF

11. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 GTL section YAG01 Spectrometer Quadrupoles YAGG1 YAGG2 Gun to Linac Diagnostics Section

12. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Gun Spectrometer Energy Absolute energy alignment using laser spectrometer field calibration Correlated Energy Spread for all charges Uncorrelated energy spread for low charges Introducing a time-energy correlation (varying injection phase) Slice thermal emittance Relay imaging system from YAG1 to spectrometer screens Point-to-point imaging in both planes Uniformity of line density Energy Absolute energy alignment using laser spectrometer field calibration Correlated Energy Spread for all charges Uncorrelated energy spread for low charges Introducing a time-energy correlation (varying injection phase) Slice thermal emittance Relay imaging system from YAG1 to spectrometer screens Point-to-point imaging in both planes Uniformity of line density 2

13. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Low Charge Operation : calibration Energy, RF phase, Uncorrelated E. Spread … Referenced to nominal  = 32  Gun spectrometer with all quadrupoles off

14. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 High Charge Operation : 1nC Nominal tuning – no quadrupole on - Longitudinal at YAG1 YAGG1

15. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 High Charge Operation : 1nC, temporal pulse, …  8% modulation Nominal phase Quadrupoles off YAG1

16. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 High Charge Operation : absolute energy spread, temporal pulse, … dephasing for introducing chirp  RF  Quadrupoles off Too large image YAG1

17. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Temporal pulse, … using quadrupoles to project on manageable size screen YAG1  RF  Quadrupoles on Resolves modulation

18. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 High Charge Operation : calibration RF phase, Correlated Energy spread, PARMELA Simulations for 1 nC Good Linearity

19. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Laser Heater Transverse RF Cavity OTR Emittance Screens DL1 Bend Straight Ahead Spectrometer Point-to-point imaging of the 75  m waist (OTR5) 3

20. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Longitudinal Phase Space at waist Transverse deflecting cavity  y / time correlation (  1mrad over 10ps ) Spectrometer  x / energy correlation Direct longitudinal Phase Space representation From PARMELA simulations (assuming 1  m emittance), resolution of less than 10 keV rmsfwhm

21. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Alternate tunings for improving emittance   th = 0.6 mm.mrad per mm laser spot size Nominal tuning r spot size = 1.2 mm,  th = 0.72 mm.mrad NameQ (nC) Laser Pulse r (mm)  th (  m.rad)  80 (  m.rad)  RF (  )   80  5% Nominal1101.20.720.9322.5 1 nC, Long pulse 117.50.850.50.75331.5 0.2nC,10ps Long pulse 0.2100.390.2340.38372.5 0.2nC,5ps0.250.420.250.37325

22. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 1nC, long pulse

23. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Very small slice emittance for 0.2 nC

24. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Conclusion http://www-ssrl.slac.stanford.edu/lcls/prd/1.2-001-r0.pdf Diagnostics were designed to provide Tools for performing correctly emittance compensation 6D characterization of beam at end of injector Diagnostics for degraded beam started Temporal Modulation laser Large emittance => impact on energy spread measurement On-line simulations tools to be chosen Fast-tracker (Homdyn, Trace3D, PARMELA …??…) MP tracker (PARMELA, ASTRA, IMPACT, GPT …??…) Data analysis tools

25. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Slice-Emittance Measurement Simulation RF-deflector at 1 MV slice OTR 10 times  y  bunch length quad scanned 4

26. Cecile Limborg-Deprey Injector Commissioning Planslimborg@slac.stanford.edu September 22 2004 Slice-Emittance Measurement Simulation slice-5 Injector at 135 MeV with S-band RF-deflector at 1 MV = meas. sim. = calc. = y distribution = actual (same SLAC slice-  code used at BNL/SDL) (slice- y -emittance also simulated in BC1-center)