Undulator Commissioning Plans Heinz-Dieter Nuhn, SLAC / LCLS October 30, 2007

1. Undulator Commissioning PlansHeinz-Dieter Nuhn, SLAC / LCLSOctober 30, 2007 • Getting the Undulator System Ready for Operation. 1

2. Getting Undulator System Ready for Operation • Installation and Rough Alignment • ADS Commissioning and Conventional Girder Alignment • Pre-Beam Checkouts • PPS Verification • Commissioning with Beam • Commissioning of Electron Beam Components • Commissioning of X-Ray Beam Diagnostics • Characterization of Spontaneous Radiation • Generation and Characterization of FEL Radiation • Transition to Operation 2

3. ADS Commissioning and Conventional Girder Alignment • ADS (WPM & HLS) Commissioning • ADS Control System Checkout • Quadrupole Alignment to Straight Line (100 microns) Monitored with ADS • Loose-End (BFW side of girder) Pre-Alignment Using Portable WPM/HLS 3

4. Pre-Beam Checkouts • HVAC System Checkout • Control System Checkout • Network Configuration of IOC's • Timing System • Communication with ADS Checkout • Verification of individual Device Operation • Magnet Power Supplies and Interlocks • BPM Cable Checkout • BPMs • Beam Finder Wire • Undulator Motion Control Checkout • CAM Mover Motion Checkout • Transverse Slide Motion Checkout • Compound Motion Checkout • Electro-Magnet Polarity Checkout • Quadrupole Main Coils Polarity Checkouts • Quadrupole Trim Coils Polarity Checkouts • BFW System Checkout 4

5. Getting Undulator System Ready for Operation • Installation and Rough Alignment • Conventional Girder Alignment • Pre-Beam Checkouts • PPS Verification • Commissioning with Beam • Electron Beam Commissioning • Commissioning of X-Ray Beam Diagnostics • Characterization of Spontaneous Radiation • Generation and Characterization of FEL Radiation • Transition to Operation 5

6. LCLS Commissioning Parameters (Inj/Lin Example) 6

7. Generic Staffing Plan • Two 8-hour shifts per day of e- • Two physicists per shift • One controls person per shift • At least one operator per shift assigned to LCLS • One engineer on call and when required for early system tests • One technician per shift (all 3) and one laser-physicist on call per shift 7

8. Electron Beam Commissioning to Tune-Up Dump • Beam and Beam Stability Characterization • Emittance • Energy Spread • Charge • Energy • Transverse and Longitudinal Profiles • Energy Dependent Optics Tuning(Electron Beam Matching) • Energy Dependent Electron Beam Steering(Launch Condition into Undulator System) • RF-Cavity BPM Commissioning(2 RF-Cavity BPMs before Tune-Up Dump) 8

9. First Beam Through Undulator Vacuum System • Conditions for First Beam: • All Undulator Magnets Rolled-Out (Quads could initially be turned off, too) • Single Shot Operation • Send single electron bunch towards undulator • Read and evaluate as much diagnostics as possible along undulator(such as BPMs, beam loss monitors, toroids) • Identify and remove sources of beam loss • Iterate • Low Charge: 200 pC or less • Diagnostics designed for micron-type resolution over 200-1000 pC range • Resolution drops proportionally for out-of-range charges. • Out-of-range resolution still sufficient for initial commissioning steps, which only requires resolution in the 100 micron range. • Goal: Get beam through vacuum chamber with minimum losses. • Reminder: Main Constraint is to Protect Undulator from Radiation Damage 9

10. First System Commissioning • (A) All Undulators in Roll-Out Position • BBA Commissioning with Undulator Segments Rolled-Out • BFW Scan with Undulator Segments Rolled-Out • ADS Check-Out with Beam • (B) Roll-In Undulators • Transport Beam through individual Undulator SegmentsStart at slot #33 (last Undulator Segment in line) • Check and correct trajectory change. • Transport Beam through multiple Undulator SegmentsStart at last • Check and correct trajectory change. • BBA Commissioning with Undulator Segments inserted. 10

11. Commissioning of X-Ray Diagnostics • Direct Imager • Calorimeter • Spectrometer • Slit • Solid Attenuator • Gas Attenuator • Ion-Chamber • Beam-Based K Measurement Components Minimum Requirement 11

12. X Ray Diagnostics 5 mm diameter collimators Soft X-Ray Offset mirror system Gas Detector Hard x-ray Monochromator (K Spectrometer) Direct Imager Solid Attenuator NFOV Slit Hard X-Ray Offset mirror system Total Energy Thermal Detector e- WFOV Gas Detector Soft X-ray Imager Start of Experimental Hutches Muon Shield Gas Attenuator 12

13. Characterization of Spontaneous Radiation • Initially at 1.5 Angstrom to reduce damage issue • Start at low charge • Repetition rate of 10 Hz or lower will be sufficient • Start to characterize radiation at last undulator Measure: • total spontaneous energy / pulse • spontaneous radiation spectrum • wavelength of first harmonic • spatial distribution around first spontaneous harmonic • first harmonic wavelength spread • spontaneous beam direction • temporal variation in spontaneous beam parameters • Characterize radiation from each individual Undulator • Measure relative K of Undulator pair. 13

14. Measure synchrotron radiation spectrum produced by two undulator segments, and scan K of one segment K’s are matched when spectrum has the steepest slope on high energy side of 1st harmonic peak. Match segments pair wise until all segments are measured. K Measurement: 2-Segment Scheme undulator segments (33 total) segments under test 14

15. Angle-Integrated Spontaneous Spectrum for 2 Undulators with DK/K = -0.2 to +0.2% Dj = 0 Simulations P. Emma Dx = 3 mm DK/K = +0.2% • 0.1% rms e- energy jitter • 0.003% rms e- energy meas. resolution • 2% rms charge jitter • 0.5% charge meas. res. • 0.5s rms angle jitter • 105 photons/pulse/0.01% • 100 photon noise • 100 beam pulses with natural energy jitter only DK/K = 0% ~106 photons/nC/0.01%BW DK/K = -0.2% 15

16. First Lasing at 15 Angstrom • Start with reduced number of undulators • Redo BBA after change of undulator configuration • Adjust tapering for spontaneous radiation losses, wakefields etc. • Verify that electron beam meets requirements • Use Laser Heater modulation method for increased sensitivity • Find SASE signal using Direct Imager or Calorimeter • Optimize Gain… 16

17. FEL Measurements • Desirable measurements as function of position along undulator : • Intensity (LG, Saturation) • Spectral distribution • Bunching • Desirable measurements after undulator : • Pulse length • Spatial shape and centroid • Divergence Saturation Exponential Gain Regime Undulator Regime 1 % of X-Ray Pulse Electron BunchMicro-Bunching 17

18. Trajectory Distortion Method z-dependent x-ray measurement using e-beam kick GENESIS Simulations by Z. Huang Quadrupole Displacement at Selectable Point along Undulator 18

19. Undulator Roll-Out Method z-dependent x-ray measurement using rollout Undulator Segments can be removed by remote control from the end of the undulator. They will not effect radiation produced by earlier segments. 19

20. LCLS FEL Commissioning (2008 - 2009) Oct 22, 2008: LTU/Undulator/Dump Ready for Beam Nov 3, 2008:Re-commission Inj./BC1/BC2/Linac to SL2 (<1 mo) Nov 25, 2008: Commission LTU up to “TDUND” (<2 mo) Jan 19, 2009: Commission Undulator & Dump (3 mo) May 14, 2009: FEE Ready for Beam (move earlier?) May 15, 2009: First Spontaneous Light May 15, 2009: FEL/FEE Commissioning (~1 mo) Jun 18, 2009: Measure photon flux density in FEE Jun 19, 2009: Commission FEE Soft X-ray Mirrors @ 15 Å (1 mo) Jul 17, 2009: X-rays in NEH Jul 31, 2009: First FEL Light Aug 1, 2009: FEL Optimization (1 mo) Sep 1, 2009: X-rays to Users in NEH @ 15 Å (1 mo) Oct 1, 2009: Shutdown for PPS Certification (1 mo) LATE (beam rate 30 Hz) Sep. 14, 2007 20

21. Summary • Plans for undulator commissioning are shaping up. • Detailed system checkout planned. • Diagnostics tools are at, or passed, the concept phase. • Beam based K-measurement method included. • Methods for gain curve measurements have been worked out. • Planned availability of x-ray diagnostics is late • Early x-ray profile and intensity diagnostics after main dump, desirable. 21

22. End of Presentation 22