LCLS Injector Commissioning P LCLS Injector Commissioning P. Emma, for the LCLS Commissioning Team LCLS DOE Review July 10, 2007 LCLS

LCLS Injector Layout 6 MeV 135 MeV 250 MeV OTR screens (7) YAG screens (7) RF Gun Wire scanners (7) Dipole magnets (8) Beam stoppers (2) L0a S-band RF acc. sections (5) Gun Spectrometer L0b Emittance Screens/Wires Emittance Screen/Wires RF Deflector 2-km point in 3-km SLAC linac L1S X-band RF acc. section 135-MeV Spectrometer BC1 TD11 stopper 135 MeV 250 MeV (not to scale)

Electron Beam Transported to All Areas April 5: First e- from gun (6 MeV) April 5: First e- to gun spectrometer (6 MeV) April 8: First e- to inj-spectrometer (135 MeV) April 14: First e- through BC1 (250 MeV) June 20: First e- through main linac (16 GeV)

Parameters and Highlights Up to 500 pC of charge (500 µJ laser energy) 10 Hz beam & 30 Hz RF (30 Hz e- also tested) RF Gun is quite reliable and performing well Transverse RF deflector working (×2) X-band RF (4th harmonic) up and running Emittance diagnostics (OTR + wires) and software working very well (gex,y  1.2 μm @ 0.5 nC) Bunch compression & possible COTR observed RF feedback systems operational Commissioning ends Sep. 4 (BC2 starts Dec. ‘07)

Pre-Beam Tunnel Check List Complete 40 pages, ~2000 checks – all DONE Polarity conventions Field type (quad, dipole) Serial numbers Installation orientation etc. etc.

RF Gun Installed in March 2007 D. Dowell breakout

e- e- Q  0.5 nC fRF = 30 Hz G  110 MV/m gex,y  1.2 mm DtFW  6.5 ps Ipk  75 A E  5.8 MeV QE  1×10-5 spec. dipole e- UV laser YAG screens solenoid Cathode (Cu) Dual RF feed RF gun

Laser Spatial and Temporal Shaping R = 0.7 mm 7.1 ps Spatial shape on cathode using iris Temporal shape (7.1 ps FWHM) Good up time and energy on cathode above spec .(500 μJ) W. White breakout

Beam on YAG02 Screen (80 cm from gun) First electron beam on April 5, 2007 20 mm

Injector Trajectory (BPMs) – Good Alignment

EPICS Controls - Vacuum H. Shoaee

EPICS Controls - Magnets

Emittance Measurements with Quad-Scans and with Multiple Profile Monitors (OTR & Wire-Scanners) H. Loos breakout Q  450 pC gex = 0.91 μm quad scan

Repetitive Emittance Measurements

Transverse RF Deflector as Diagnostic RF deflector OFF RF deflector ON RF deflector ON head  high E tail Screen image with RF deflector OFF (left) and ON (middle), for measuring sliced emittance. A 2nd screen after a bend (right), with deflector ON, shows longitudinal phase space.

Measured Temporal Distribution of Bunch Temporal distribution of e- beam measured with the transverse RF deflector upstream of BC1.

Time-sliced Emittance Measured Routinely gex ~1 ps C. Limborg breakout Time-sliced x-emittance measured on pre-BC1 OTR screen using quad-scan at 0.2 nC and 0.7-mm cathode spot radius. Each slice is about 1 ps wide.

motor controlled translation stage X-Band RF (11.4 GHz) and BC1 Chicane are Fully Operational BPM for energy feedback (20 mm resolution) Offset: 0 to 26 cm (23 cm nominal) collimator BPM tweaker quadrupoles OTR screen motor controlled translation stage J. Frisch breakout RF deflector OFF RF deflector ON Deflector ON & X-band ON X-band correction energy chirp only

Residual Dispersion Measurements & Correction BPM Scan energy… BPM B2 B3 BPM BPM B1 B4 S-band acc. CQ11 CQ12 Read BPMs… …set quads BC1 Assumes e0 = 1 μm & sd = 1.6% Before correction After CQ11/CQ12 correction

BC1 Dipole Field Quality Poor quads use to correct ‘CQ’ quads off nominal x-position dipoles need work

Bunch Compression Observed with CER L1S-linac RF phase: j = 0º j = 15º j = 20º j = 25º j = 30º j = 35º j = 40º Coherent edge radiation (CER) detector after BC1

Hor. emittance growth in X-band RF L1S X-band RF acc. section BC1 stopper gex Dx = 1.2 mm gey ~65 μrad pk (1.3 keV) X-band RF ON X-band RF OFF x kick at downstream BPM

Transverse Wakefield in X-Band Structure Q  500 pC BC1 OFF X-band RF OFF gex (μm) Dx = +0.6 mm

LCLS Beam Down SLAC Linac with 500 pC and up to 16 GeV end of linac screen 1 km

2007 Injector Commissioning Goals DONE DONE DONE http://www-ssrl.slac.stanford.edu/lcls/internals/commissioning/documents/lclsinjector-commissioninggoals.doc DONE ~DONE DONE CONTINUES STARTED

LCLS Installation and Commissioning Time-Line June 29, 2007 linac/BC2 Install LTU/Und/Dump FEE/NEH Install First Spont. Light X-Ray tunnel/FEH Install now CD-4a J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D 2007 2008 2009 PPS PPS Controls checkout & re-commission injector Re-commission Inj/BC2 to SL2 …Injector Commissioning Linac/BC2 Commissioning LTU/Und/FEE Commissioning FEL Commissioning

Problems/Issues Gun Faraday cup & toroid not functioning BC1 motion control limited (300 mm  260 mm) Cathode QE 3-10 times below design (improving!) Some controls tools late (orbit displays, fitting, magnet control & alarms) Laser phase drift and lock trouble until mid-June Hor. emittance growth from X-band RF (?) BC1 dipole field quality poor

Summary Beam transported to all areas (no major problems) No obstructions or ‘backwards’ components (except laser alignment mirror) BC1 & X-band emittance preservation problems Controls still developing, but working well and improving fast – great cooperation and effort Matlab control tools are indispensable Communication with laser group excellent BC2/Linac commissioning starts in Dec. ’07 GREAT commissioning team! (see breakout talks) Thanks to all – results are quite positive (in spite of my constant whining)