1. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Undulator / FEL Commissioning Plans Heinz-Dieter Nuhn, SLAC / SSRL September 22, 2004 FY2004 Undulator Parameter Changes Summary of January Undulator Commissioning Workshop Undulator Commissioning Issues FEL Characterization FY2004 Undulator Parameter Changes Summary of January Undulator Commissioning Workshop Undulator Commissioning Issues FEL Characterization

2. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Linac Coherent Light Source Near Hall Far Hall Undulator

3. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu

4. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu FEL Design Changes Since the May 2003 Lehman Review Canting of Undulator Poles Remote Undulator Roll-Away and K Adjustment Function Increase in Undulator Gap Reduction in Maximum Beam Energy Reduction in Quadrupole Gradient Increase in Beta Function Increase in Break Section Length  Electromagnetic Quadruples Canting of Undulator Poles Remote Undulator Roll-Away and K Adjustment Function Increase in Undulator Gap Reduction in Maximum Beam Energy Reduction in Quadrupole Gradient Increase in Beta Function Increase in Break Section Length  Electromagnetic Quadruples

5. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu New: Undulator Pole Canting Canting comes from wedged spacers 4.5 mrad cant Gap can be adjusted by lateral displacement of wedges 1 mm shift means 4.5 microns in gap, or 8.2 Gauss B eff adjusted to desired value Courtesy of Liz Moog Suggested by J. Pflueger, DESY

6. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Undulator Roll-Away and K Adjustment Function Neutral; K=3.4965;  x=+0.0 mmFirst; K=3.5000;  x=-1.5 mm Last; K=3.4929;  x=+1.5 mmRollAway; K=0.0000;  x=+100 mm PowerTp; K=3.4804;  x=+7.0 mm

7. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Effective B field vs. x Measured slope of 6.6 Gauss/mm agrees with calculations (~ 5.7 Gauss/mm for 3 mrad cant) Field variation allowance between segments is  B/B = 1.5x10 -4, or  B = 2 Gauss, which translates to  x = 0.3 mm ( or 1 micron in gap) Courtesy of Liz Moog

8. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Canting the poles helps in many ways Facilitates final setting of B eff Remote control of position allows run-time adjustment Allows compensating for temperature effect on field strength: ±1.0°C temperature error would require ±1.2 mm lateral shift of undulator Courtesy of Liz Moog

9. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu RMS phase error at different x positions No significant dependence on X An RMS phase error of ~ 6.5 degree is an upper limit for near- perfect (~100%) performance Courtesy of Liz Moog

10. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Period-averaged horizontal trajectories at 14.1 GeV Trajectories are all well behaved and well within the 2  m tolerance for maximum walk-off from a straight line (X in mm) Courtesy of Liz Moog

11. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu May 2003August 2004 Undulator Type planar hybrid Magnet Material NdFeB Wiggle Planehorizontal Gap6.06.8mm Gap Canting Angle0.04.5 mrad Period Length 30.0 ± 0.1mm Effective On-Axis Field1.3251.249 T Effective Undulator Parameter K3.630 ± 0.015% 3.500 ± 0.015% Module Length 3.40m Number of Modules 33 Undulator Magnet Length112.2m Standard Break Lengths18.7 - 18.7 - 42.1 48.2 - 48.2 - 94.9 cm Total Device Length121.0 131.9 m Lattice Type FODO Integrated QF Gradient 5.355 3.000 T/m Integrated QD Gradient-5.295 -3.000 T/m Average  Function at 1.5 Å 18 30m Average  Function at 15. Å7.3 8.9 m May 2003August 2004 Undulator Type planar hybrid Magnet Material NdFeB Wiggle Planehorizontal Gap6.06.8mm Gap Canting Angle0.04.5 mrad Period Length 30.0 ± 0.1mm Effective On-Axis Field1.3251.249 T Effective Undulator Parameter K3.630 ± 0.015% 3.500 ± 0.015% Module Length 3.40m Number of Modules 33 Undulator Magnet Length112.2m Standard Break Lengths18.7 - 18.7 - 42.1 48.2 - 48.2 - 94.9 cm Total Device Length121.0 131.9 m Lattice Type FODO Integrated QF Gradient 5.355 3.000 T/m Integrated QD Gradient-5.295 -3.000 T/m Average  Function at 1.5 Å 18 30m Average  Function at 15. Å7.3 8.9 m Amplitudes of FEL Parameter Changes

12. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu May 2003August 2004Change Electron Beam Energy14.3513.64GeV-5.0 % Emittance0.0430.045nm rad+5.2 % Avg. Electron Beam Radius2735µm+27.5 % Avg. Electron Beam Divergence1.61.3µrad -17.5 % Peak Beam Power4946TW-5.0 % FEL Parameter (3D)0.00033 0.00032 -3.5 % Power Gain Length (3D)4.24.3 m+3.6 % Saturation Length (w/o Breaks)8286m+4.9 % Saturation Length (w/ Breaks)89101m+13.5 % Peak Saturation Power7.47.6GW+2.5 %* Coherent Photons per Pulse1.4×10 12 1.5×10 12 +2.5 %* Peak Brightness1.5×10 33 1.5×10 33** +2.5 %* Average Brightness4.6×10 22 4.7×10 22** +2.5 %* Peak Spont. Power per Pulse9173GW-19.7 % *Increase due to 3D effects (reduction in diffraction due to beam radius increase) ** [Ph./s/mm 2 /mr 2 /.1%] May 2003August 2004Change Electron Beam Energy14.3513.64GeV-5.0 % Emittance0.0430.045nm rad+5.2 % Avg. Electron Beam Radius2735µm+27.5 % Avg. Electron Beam Divergence1.61.3µrad -17.5 % Peak Beam Power4946TW-5.0 % FEL Parameter (3D)0.00033 0.00032 -3.5 % Power Gain Length (3D)4.24.3 m+3.6 % Saturation Length (w/o Breaks)8286m+4.9 % Saturation Length (w/ Breaks)89101m+13.5 % Peak Saturation Power7.47.6GW+2.5 %* Coherent Photons per Pulse1.4×10 12 1.5×10 12 +2.5 %* Peak Brightness1.5×10 33 1.5×10 33** +2.5 %* Average Brightness4.6×10 22 4.7×10 22** +2.5 %* Peak Spont. Power per Pulse9173GW-19.7 % *Increase due to 3D effects (reduction in diffraction due to beam radius increase) ** [Ph./s/mm 2 /mr 2 /.1%] Performance Impact of Changes (1.5 Å)

13. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Undulator / FEL Commissioning Documents “Report of the LCLS Diagnostics and Commissioning Workshop” SLAC-R-715, LCLS-TN-04-02 http://www-ssrl.slac.stanford.edu/lcls/technotes/LCLS-TN-04-2.pdf http://www-ssrl.slac.stanford.edu/lcls/technotes/LCLS-TN-04-2.pdf LCLS PRD1.1-002 “LCLS Start-Up Test Plan” http://www-ssrl.slac.stanford.edu/lcls/prd/1.1-002-r0.pdf http://www-ssrl.slac.stanford.edu/lcls/prd/1.1-002-r0.pdf

14. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Undulator Diagnostics and Commissioning Workshop 1/19-20/04 Scope Commissioning of the FEL Undulator with Beam Goals End-Of-Construction Goal Defined by DOE to close-off construction project (CD-4) One of the first Commissioning Milestones Commissioning Goal Get LCLS ready for operation Prerequisites Undulator, Diagnostics, Shielding, Beam Dump etc. in Place Commissioning Without Beam for all Components Complete Main Commissioning Tasks Characterization of Electron Beam Up-Stream of Undulator Establishment of a Good Beam Trajectory Through Undulator to Beam-Dump Characterization of Spontaneous Radiation Establishment of SASE Gain Characterization of FEL Radiation Scope Commissioning of the FEL Undulator with Beam Goals End-Of-Construction Goal Defined by DOE to close-off construction project (CD-4) One of the first Commissioning Milestones Commissioning Goal Get LCLS ready for operation Prerequisites Undulator, Diagnostics, Shielding, Beam Dump etc. in Place Commissioning Without Beam for all Components Complete Main Commissioning Tasks Characterization of Electron Beam Up-Stream of Undulator Establishment of a Good Beam Trajectory Through Undulator to Beam-Dump Characterization of Spontaneous Radiation Establishment of SASE Gain Characterization of FEL Radiation Low Charge Single Shot Low Charge, 10 Hz 10 Hz

15. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu January 2004 Workshop Recommendations No Intra-Undulator-Segment X-Ray Diagnostics in Baseline Design Instead: End-of-Undulator X-Ray Diagnostics to Characterize FEL Radiation vs. z Trajectory Distortion Method Roll-Away Undulator Segments Function Investigation of Spontaneous Radiation as Diagnostics Tools Code Development to Support Commissioning Areas for Follow-Up R&D Study of Spectral and Spatial Distribution of Spontaneous Radiation Diagnostics Prototyping Microbunching Measurement No Intra-Undulator-Segment X-Ray Diagnostics in Baseline Design Instead: End-of-Undulator X-Ray Diagnostics to Characterize FEL Radiation vs. z Trajectory Distortion Method Roll-Away Undulator Segments Function Investigation of Spontaneous Radiation as Diagnostics Tools Code Development to Support Commissioning Areas for Follow-Up R&D Study of Spectral and Spatial Distribution of Spontaneous Radiation Diagnostics Prototyping Microbunching Measurement

16. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Commissioning Phases Phase 0: Beam Through Undulator (at 0.2 nC, sngl shot) Phase I: Spontaneous Radiation (at 0.2 nC, 10 Hz) Parameters: Energy 4.31-13.64 GeV, Emittance: not critical Goals: Establish straight and stable trajectory, measure spontaneous radiation Phase II a: Low Energy FEL Radiation (at 0.2-1 nC, 10 Hz) Parameters:Energy: 4.31 GeV, Emittance: < 4 microns Peak Current : < 1 kA Goals: Characterize FEL radiation. Achieve saturation. Phase II b: High Energy FEL Radiation (at 0.2-1 nC, 10 Hz) Parameters:Energy: >4.31 -13.64 GeV, Emittance: 1.2- 4 microns Peak Current : 1-3.4 kA Goals: Characterize FEL radiation, gain. Achieve saturation. Phase III: Transition to Operation (at 0.2-1 nC, 120 Hz) Parameters:Energy: >4.45 -13.64 GeV, Emittance: 1.2- 4 microns Peak Current : 1-3.4 kA Goals: Bring FEL performance up to full operating performance levels.

17. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu LTU / Undulator Commissioning Issues Undulator Radiation Protection Collimators Tune-Up Dump Roll-Away Undulators Radiation Interlocks Measurements of FEL Radiation vs. Z Radiation Power Damage to Inter Undulator X-Ray Diagnostics End-of-Undulator Diagnostics Beam Based Detection of Gain Reducing Errors Using Spontaneous Radiation Using FEL Gain Curve Numerical Simulation Support for Detector Development and Commissioning Undulator Radiation Protection Collimators Tune-Up Dump Roll-Away Undulators Radiation Interlocks Measurements of FEL Radiation vs. Z Radiation Power Damage to Inter Undulator X-Ray Diagnostics End-of-Undulator Diagnostics Beam Based Detection of Gain Reducing Errors Using Spontaneous Radiation Using FEL Gain Curve Numerical Simulation Support for Detector Development and Commissioning See next talk by Sven Reiche !

18. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu  /2  /2 x1x1x1x1 x2x2x2x2 x3x3x3x3 phase-1 phase-2 phase-1 again halo e  beam mm  3 mm 2 mm  2 mm Two-Phase, Two-Plane Collimation, 1½ Times undulator beam pipe 5 mm  2.5 mm edge scattering (also collimation in y and energy – see next slides) Undulator Radiation Protection Courtesy of Paul Emma

19. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu E1E1E1E1 E2E2E2E2 x1x1x1x1 y1y1y1y1 x2x2x2x2 y2y2y2y2 x3x3x3x3 y3y3y3y3 LCLS Collimation Proposal (2 energy, 3 x, and 3 y adjustable collimators) muon shielding undulator x 3 & y 3 optional? Courtesy of Paul Emma

20. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu 2 nd -order tracking with all collimators closed and big halo  2.5 mm 2-phase, 2-plane, and energy collimation in 2 nd -order well shadowed in x, y, and E ?- CY3 -? CX3  2.0- CY2 -  2.0 CX2  2.0- CY1 -  2.0 CX1 -  5.0 CE2 -  5.0 CE1  y mm  x mm Coll.  x,y = 4000  m,  E /E = 10% (uniform) Courtesy of Paul Emma

21. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu G = 110 T/m Track 100 times with: DL2 BPM rms res. = 10  m DL2 BPM rms misa. = 200  m DL2 Quad rms misa. = 200  m Undulator Quad rms misa. = 100  m Correct und-launch, then open stopper-2 for one beam shot… Just 11 of 100 trajectories exceed  2.5 mm within undulator None exceed  3.5 mm First beam shot through undulator? Courtesy of Paul Emma

22. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Desirable measurements as function of position along undulator : Intensity (LG, Saturation) Spectral Distribution Bunching Total energy Pulse length Photon energy spectra Spatial coherence Spatial shape and centroid Divergence Desirable measurements as function of position along undulator : Intensity (LG, Saturation) Spectral Distribution Bunching Total energy Pulse length Photon energy spectra Spatial coherence Spatial shape and centroid Divergence FEL Gain Measurement Undulator Regime Exponential Gain Regime Saturation 1 % of X-Ray Pulse Electron Bunch Micro-Bunching

23. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Quantities to be Measured Total energy Pulse length Photon energy spectra Spatial coherence Spatial shape and centroid Divergence Total energy Pulse length Photon energy spectra Spatial coherence Spatial shape and centroid Divergence

24. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Dose / Power Considerations Fluence to Melt Energy Density Reduction of a Reflector Be will melt at normal incidence at E < 3 KeV near undulator exit. Using Be as a grazing incidence reflector may gain x 10 in tolerance. Courtesy of Richard Bionta

25. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Measurement of SASE Gain along the undulator Direct: Detectors in the Breaks between Undulator Segments. Fluence levels too large for x-ray!. Alternative: End-Of-Undulator Diagnostics Turn-Off Gain at Selectable Point Along Undulator by Introduction of trajectory distortion Removal of undulator segments (New roll-away option) Characterize x-ray beam at single station down stream of undulator Direct: Detectors in the Breaks between Undulator Segments. Fluence levels too large for x-ray!. Alternative: End-Of-Undulator Diagnostics Turn-Off Gain at Selectable Point Along Undulator by Introduction of trajectory distortion Removal of undulator segments (New roll-away option) Characterize x-ray beam at single station down stream of undulator

26. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Fast close valve Slit A PPS 13' Muon shield Gas Attenuator Solid Attenuator Slit B PPS 4' Muon shield Windowless Ion Chamber Direct Imager Indirect Imager Spectrometer, Total Energy PPS Access Shaft Access Shaft Courtesy of Richard Bionta

27. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Measurement of SASE Gain with Trajectory Distortion GENESIS Simulations by Z. Huang Quadrupole Displacement at Selectable Point along Undulator

28. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Measurement of SASE Gain Using Rollaway Option Undulator Segments can be removed by remote control from the end of the undulator. They will not effect radiation produced by earlier segments.

29. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Spontaneous vs. FEL Radiation Spontaneous vs. FEL Radiation-1- Figure by S. Reiche See Thursday talk by Paul Emma Weak FEL Signal Detection Using a Slowly Modulated Laser-Heater See Thursday talk by Paul Emma Weak FEL Signal Detection Using a Slowly Modulated Laser-Heater

30. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Spontaneous vs. FEL Radiation Spontaneous vs. FEL Radiation -2- Figure by S. Reiche

31. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu Conclusions Several Undulator Parameters have been Changed. New K Adjustment and Roll-Away Option will aid undulator and FEL commissioning. FEL and Spontaneous Radiation Diagnostics will be located after the end of the undulator Detailed commissioning strategy is being developed. First Startup Test Plan exists. PRD 1.1-002 LCLS Start-Up Test Plan (http://www-ssrl.slac.stanford.edu/lcls/prd/1.41002-r1.pdf)http://www-ssrl.slac.stanford.edu/lcls/prd/1.41002-r1.pdf Several Undulator Parameters have been Changed. New K Adjustment and Roll-Away Option will aid undulator and FEL commissioning. FEL and Spontaneous Radiation Diagnostics will be located after the end of the undulator Detailed commissioning strategy is being developed. First Startup Test Plan exists. PRD 1.1-002 LCLS Start-Up Test Plan (http://www-ssrl.slac.stanford.edu/lcls/prd/1.41002-r1.pdf)http://www-ssrl.slac.stanford.edu/lcls/prd/1.41002-r1.pdf

32. Undulator Commissioning September 22, 2004 Heinz-Dieter Nuhn, SLAC / SSRL LCLS Commissioning Workshop Nuhn@slac.stanford.edu End of Presentation