LCLS Commissioning LCLS Commissioning (Phase I) (Phase I) C.Limborg-Deprey C.Limborg-Deprey LCLS, SLAC LCLS, SLAC Sept.24th 2007 Sept.24th 2007 Sept. 24 Sept. 24 th th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Outline Outline 1. LCLS Project Overview 2. Injector Commissioning – Laser, Gun, Cathode, … – Electron Beam Measurements – Some interesting beam physics … 3. Comparison with simulations Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
PART 1: LCLS Project Sept. 24 Sept. 24 th th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Linac Coherent Light Source at SLAC SLAC Linac Coherent Light Source at X-FEL based on last 1-km of existing linac X-FEL based on last 1-km of existing linac Injector (35º º) ) Injector (35 1.5-15 Å at 2-km point 1.5-15 Å at 2-km point Existing 1/3 Linac (1 km) Existing 1/3 Linac (1 km) (with modifications) (with modifications) − Transfer Line (340 m) e − New e Transfer Line (340 m) New X-ray X-ray LLNL LLNL Transport Undulator (130 m) Transport Undulator (130 m) Line (200 m) Line (200 m) Near Experiment Hall Near Experiment Hall (underground) (underground) Far Experiment Far Experiment Hall (underground) Hall (underground) Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
3 rd rd vs vs 4 4 th th Generation Light Sources Generation Light Sources 3 … ~ 15 years old Spring8,Japan + newer SLS, SPEAR3,SOLEIL… APS, USA ESRF, Europe 3 rd GLS 4 th GLS Peak Brilliance 5.10 23 10 33 Coherent flux 10 10 /s /0.01% 10 13 / s/0.01% σ ~ 10ps σ ~ 100 fs (*) Pulse Length under (*) or less with less flux construction X-FEL,Germany SCSS, Japan LCLS, USA Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
4 th th Generation Light Sources Generation Light Sources 4 Peak Brilliance 10 orders of magnitude > that of 3 rd GLS ➘ 2 from bunch length (10ps 100fs) 2 from ➘ bunch length (10ps 100fs) 2 from ➘ in horizontal emittance emittance (3nm (3nm 0.03nm) 2 from ➘ in horizontal 0.03nm) 1 from smaller divergence (SASE) 1 from smaller divergence (SASE) 2 from longer undulator undulator (~ 100m) (~ 100m) 2 from longer 3 from FEL gain (SASE) (SASE) 3 from FEL gain But: 3 rd GLS High repetition rate & High average brilliance Stability decoupled from that of injector Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Nominal LCLS Parameters Fundamental FEL Radiation Wavelength 1.5 15 Å Electron Beam Energy 14.3 4.5 GeV Normalized RMS Slice Emittance 1.2 1.2 mm-mrad Peak Current 3.4 3.4 kA Bunch/Pulse Length (FWHM) 230 230 fs Relative Slice Energy Spread <0.01 0.025 % Saturation Length 87 25 m FEL Fundamental Saturation Power 8 17 GW FEL Photons per Pulse 1.1 29 10 12 Peak Brightness @ Undulator Exit 0.8 0.06 10 33 * Transverse Coherence Full Full RMS Slice X-Ray Bandwidth 0.06 0.24 % RMS Projected X-Ray Bandwidth 0.13 0.47 % * photons/sec/mm 2 /mrad 2 / 0.1%-BW Sept. 24 Sept. 24 th th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
LCLS e-beam requirements LCLS e-beam requirements ε N = 1.2 mm-rad P = P 0 ε N = 2.0 mm-rad P = P 0 /100 courtesy S. Reiche ε x/y,n < 1.2 mm-mrad • Slice emittance Slice energy spread σ δ < 10 -4 • 3.4 kA ( σ τ ~ 150 fs) • High Peak Current • Stability dQ/Q < 2% rms (P ➘ 30 %) Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Nominal LCLS Parameters µ m Single bunch, 1-nC charge, 1.2- µ m slice slice emittance, 120-Hz repetition rate emittance, 120-Hz repetition rate… … Single bunch, 1-nC charge, 1.2- 6 MeV 250 MeV 4.30 GeV 13.6 GeV 6 MeV 135 MeV 250 MeV 4.30 GeV 13.6 GeV 135 MeV σ z ≈ 0.83 mm σ z σ z ≈ ≈ 0.19 mm σ σ z z ≈ ≈ 0.020 mm σ z σ z ≈ ≈ 0.020 mm σ z ≈ σ z σ z ≈ ≈ 0.83 mm 0.83 mm 0.19 mm 0.020 mm 0.020 mm 0.83 mm σ δ ≈ 0.05 % σ δ ≈ 1.6 % σ δ ≈ 0.71 % σ δ ≈ 0.01 % σ ≈ σ δ ≈ 0.10 % σ ≈ σ ≈ σ ≈ σ ≈ 1.6 % 0.71 % 0.01 % 0.05 % 0.10 % δ δ δ δ δ Linac- Linac- X X Linac-0 Linac-0 L =0.6 m =0.6 m L L =6 m =6 m L rf rf ϕ rf ϕ = − 160 − 160° ° rf = gun gun Linac-3 Linac-3 Linac-1 Linac-1 Linac-2 Linac-2 L 0 ≈ 550 m ≈ 9 m ≈ 330 m L ≈ - L ≈ L ≈ 550 m a 9 m 330 m L L L , b ϕ rf ≈ 0° ϕ rf ≈ − 25° ϕ rf ≈ − 41° ϕ rf ≈ ϕ rf ≈ − ϕ rf ≈ − 0° 25° 41° ...existing 25-1a 21-1 21-3b undulator undulator X 30-8c linac b,c,d 24-6d L =130 m =130 m L BC1 BC1 BC2 BC2 ≈ 6 m ≈ 22 m L ≈ L ≈ L 6 m L 22 m DL1 DL1 56 ≈ ≈ − − 39 mm 56 ≈ ≈ − − 25 mm ≈ 12 m L ≈ R 56 R 39 mm R 56 R 25 mm DL2 DL2 L 12 m 56 ≈ ≈ 0 R 56 R 0 L =275 m L =275 m ≈ 0 56 ≈ R 56 0 R SLAC linac tunnel SLAC linac tunnel research yard research yard Installation Summer 06 Fall 07 Year 08 Commissioning April. -> Aug 07 Jan. 08 Spring 09 Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
PART 2: LCLS Injector Commissioning Sept. 24 Sept. 24 th th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Injector and 1 st st Bunch Compressor commissioning Bunch Compressor commissioning Injector and 1 6 MeV 6 MeV OTR screens (7) OTR screens (7) YAG screens (7) YAG screens (7) RF Gun RF Gun Wire scanners (7) Wire scanners (7) Dipole magnets (8) Dipole magnets (8) Beam stoppers (2) Beam stoppers (2) L0a L0a S-band RF acc. sections (5) S-band RF acc. sections (5) Gun L0b L0b Gun Spectrometer Spectrometer Emittance Emittance Emittance Emittance Screens/Wires Screens/Wires Screen/Wires Screen/Wires RF RF Deflector Deflector L1S L1S 2-km point in 3-km SLAC linac 2-km point in 3-km SLAC linac X-band RF X-band RF BC1 BC1 135-MeV 135-MeV TD11 TD11 acc. section acc. section Spectrometer Spectrometer stopper stopper 135 MeV 250 MeV 135 MeV 250 MeV (not to scale) (not to scale) Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
First Photo-Electrons, April 5, 2007 First Photo-Electrons, April 5, 2007 Photo-Electrons: First Photo-Electrons!!! After adjusting laser-gun phase Dark Current Sept. 24 Sept. 24 th th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Commissioning Milestones Commissioning Milestones • Spring 2006: Civil construction of buildings/shielding completed • Summer 2006: Drive Laser Installed • Fall 2006: Drive laser commissioned & Gun1 high power conditioning in Klystron Lab • Spring 2007: Injector & BC1 beamline installed • March 16, 2007: RF gun installed & RF processing started • April 5, 2007: First Photo-electrons • April 9, 2007: E-beam to 135 MeV • April 16, 2007: E-beam to 250 MeV & compressed in BC1 • June 24, 2007: E-Beam to 15 GeV (200pC) • July 24, 2007: E-Beam studies at 1 nC • July 26, 2007: E-Beam at 1nC to 15 GeV • August 8, 2007: Compressed 1 nC e-beam to 15 GeV • August 2007: Injector Meets LCLS Requirements Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Thales Drive Laser System Thales Drive Laser System Measuring 150-200fs 1.0mx1.5m breadboard phase stability from osc. 119MHz >300ps >600mW Femtolasers Synergy 5 nm Stretcher DAZZLER Oscillator 4W Regen Amp 15mJ Spectra Physics >1.5mJ, 120Hz 120 Hz MILLENNIA Vs JEDI #1 Pulse Picker 100 mJ,120 Hz UV-diagnostics: >1mJ, 120Hz Streak camera Pre-Amp Spectrometer Cross-correlator 4-pass Bowtie 75mJ TG-Frog… 120 Hz >22mJ, 120Hz ~12m to cathode UV Transport Amplifier JEDI #2 THG Compressor to Cathode 2-pass Bowtie 100 mJ,120 Hz 80mJ >3mJ >30mJ >40mJ 120 Hz 120Hz 120Hz 120Hz 1.0mx1.5m breadboard >0.4mJ, 120Hz 255 nm Slide compliments Ph. Hering Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
Laser stability vs. time Drive Laser Performances Drive Laser Performances 1.1% charge stability at 1nC, 2% is spec •Laser reliability is very good: Up-time > 90% •Excellent support from Thales & Femtolasers • E ~ 400 µ J to cathode (250 µ J spec) •Shaping needs work, but still producing good emittances •Excellent energy stability (1.1%) •Position stability on cathode, ~10-20 µ m X-Correlator Measurement of Laser Pulse Image of Laser Profile on Virtual Cathode Camera Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
RF Gun: 1.6 cell S-Band RF Gun: 1.6 cell S-Band Modified from BNL/UCLA/SLAC design • Z-coupling: – reduces pulsed heating – increases vacuum pumping • Racetrack to minimize quadrupole fields • Deformation tuning to eliminate field emission from tuners Increased 0- π mode separation to 15MHz • • Iris reshaped, reduces field 10% below cathode RF Parameters f p (GHz) 2.855987 Q0 13960 β 2.1 Mode Sep. Δ f (MHz) 15 Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
RF Gun: Processing and Operation RF Gun: Processing and Operation • Conditioning – 60Hz, 120 MV/m – 120Hz , 107 MV/m due to heating of probes • Operation 30 Hz, 110MV/m, 1 µ s klystron pulse – – 3.10 8 pulses (from April to Aug 07) Courtesy E.Jongewaard Sept. 24 th Sept. 24 th 07, LAL Talk 07, LAL Talk limborg@slac.stanford.edu
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