2. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Injector Commissioning Injector Commissioning Results presentated to the Facilities Advisory Committee, October 2007, by J. Welch on behalf of the LCLS Commissioning Team.

3. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Introduction Last April Today Commissioning plans

4. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Injector Layout OTR screens (7) YAG screens (7) Wire scanners (7) Dipole magnets (8) Beam stoppers (2) S-band RF acc. sections (5) RF Gun GunSpectrometer RFDeflector X-band RF acc. section BC1 L1S L0a L0b 2-km point in 3-km SLAC linac 135-MeVSpectrometer EmittanceScreens/Wires EmittanceScreen/Wires 135 MeV 6 MeV 250 MeV TD11stopper (not to scale) UV laser

5. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Summary April 16, 2007 (Last FAC Meeting) Beam transported to all areas. No trouble, but no systematic checkout yet. Controls still under development, but working well and improving fast – great cooperation and effort Communication with laser group excellent Screens and toroids late, but installation continued Some quality control issues with a few components April 5: First e  from gun (6 MeV) April 8: First e  to inj-spectrometer (135 MeV) April 14:First e  through BC1 (250 MeV)

6. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Where We are Now Commissioning Results All Injector Commissioning Goals achieved x & y emittance 1.2  m at 1 nC charge (design) <1.5% rms charge stability (design is 2%) Drive laser 98% up-time with 500  J (250 design) Bunch compression in BC1 fully demonstrated Accelerated LCLS beam to 16 GeV (13.6 design) X-band & 2 RF deflectors both operational New RF performing within spec (e.g., <0.1º rms) Feedback ON: launch, charge, energy, RF, &  z Robust, high-quality RF gun Remaining problems Gun Faraday cup and toroid don’t work BC1 dipole field quality is poor Emittance growth from X-band RF OTR beam size measurements altered by COTR Bunch length from injector 30% too long (1.1 mm, but design is 0.85 mm) Wire-scanners vibrate Improvements underway

7. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 2007 Injector Commissioning Goals http://www- ssrl.slac.stanford.edu/lcls/internals/commissioning/documents/l clsinjector-commissioninggoals.doc

8. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Laser Performance 98% up-time with 500  J (250  J design). Spatial profile and position stability were initially poor, but improved greatly by extending the length of the drift tubes. Temporal shape (7.1 ps FWHM) Spatial shape on cathode using iris 7.2 ps 8.8 ps P. Hering. Oct. 8 R = 0.8 mm

9. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Emittance Performance design emittance

10. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Gun QE Performance Now up to 1 nC Emission Image of Cathode on YAG <1.5% rms charge stability (design is 2%)

11. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 EPIC Controls Magnets LLRF Collimator Vacuum MPS User App. Launcher Heroic and successful effort by the Controls Group Also use SLC Controls

12. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Matlab Application Emittance Measurement - H. Loos Example: emittance measurement Measure emittance at chosen location using 3 OTRs, 3 wires, or quad scan on OTR or wire Watch profiles as scan proceeds (avg. ~10) Send results to E-log

13. Transverse Wakefield in X-Band Structure  x  0.6 mm Q  700 pC  z  1 mm E = 250 MeV BC1 OFF X-band RF OFF  x (μm) J. Turner X-Band cavity to be re-aligned during this downtime.

14. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Time Resolved Measurements RF deflector OFF RF deflector ON head tail  high E  E  6 keV rms (40  m) at 150 pC in spectrometer

15. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 14 GeV ‘Max’ Compression 0.89 ps 14 GeV 135 MeV 1.10 mm rms 14 GeV BC1 Design Compression 10.3 ps 135 MeV 97 A 950 A 520 A 1.7 ps 14 GeV PR55 Thanks to Controls Group OTR2 135 MeV 14 GeV Bunch Length Measurements

16. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Unexpected Physics! Coherent OTR Bunch Length Monitors OTROpticalSignal 300 GHz 100 GHz RF Phase of L1S, relative to crest (degS) Generation of COTR in the Visible Spectrum Indicates Micro-bunch Spike & Interferes with Using OTR Profiles for Emittance Measurements. (~Frisch, Tues 11:30) At max compression OTR Can Produce “Ring-Like” Shapes! OTR Light increases by 10-100 with maximum compression

17. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 B1B1 B2B2B3B3 B4B4 TD11TD11 S-band acc. BPM BPM BPMBPM wire scan after BC1:  x  1.7  m poor bend field quality quads correct  x nominal x-position quadsoff read dnstr. BPMs while moving BC1 OTR wire(s) CQ11CQ12 Best  x after BC1 with nom. (& more) compression is 1.7  m (& larger) Poor bend field quality (grad. + sext.) –  E/E scan shows 1 st & 2 nd -order  x Bends being upgraded + need shorter bunch (1.1  0.85 mm – less chirp) Best  x after BC1 with nom. (& more) compression is 1.7  m (& larger) Poor bend field quality (grad. + sext.) –  E/E scan shows 1 st & 2 nd -order  x Bends being upgraded + need shorter bunch (1.1  0.85 mm – less chirp) best emittance transfer  x minimized with quads BC1 Emittance Growth

18. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Fix for BC1 Dipoles Modifications include wider poles (180 instead of 100 mm) and new pinning scheme for yokes.

19. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Commissioning Plans 1.1.2 km of existing linac (including new bunch compressor BC2) 2.~308 m of new transport line, LTU, up to Tune-up Dump at the beginning of Undulator hall. 3.200 m of Undulator and Dump Line 4.Commission the FEL X-Ray beam itself 5.Commission the X-Ray diagnostics and beamlines “FEE” X Ray Diagnostics “NEH” hutches Xray Tunnel Existing and refurbished housing Undulator New housing construction. Completion by ~ Mar. 08 LTU: Linac to Undulator FEE: Front End Enclosure NEH: Near Experimental Hall FEH: Far Experimental Hall BC1(2): Bunch compressors Electron Dump “FEH” hutches Injector Linac BC1 250 MeV BC2 4 GeV “LTU” Frisch Welch Nuhn Tompkins

20. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Linac/BC2 FEE/NEH/X-Ray Tunnel/FEH Installation Timeline of Installation and Commissioning JASONDJFMAMJJASONDJFMAMJJ Linac/BC2 Commissioning 20072008 LTU/Und/Dump Commissioning ASOND 2009 PPS Controls checkout & re-commission Injector Re-commission Inj/BC2 to SL2 FEL/FEE Commissioning …InjectorCommissioning Now PPS 1st Spont. Light 1st Users downtime commissioning LTU/UND/Dump Installation 1st FEL Light installation

21. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 FEL Commissioning Timeline

22. James Welch FACWelch@SLAC.Stanford.edu October 29, 2007 Thanks to All ! Commissioners Laser Group OperationsControls Power Conversion MFDVacuumFacilities Acc. R&D Metrology ES&H (RP) Mechanical Design Materials Science FacilitiesKlystron/RFSSRL/GTF Acc. Systems LCLS project personnel Results are very positive and credited to a large, dedicated group of people at SLAC Core group: 3 shifts/week no weekends off 5 months + R. Iverson, J. Schmerge… + R. Iverson, & J. Schmerge…