PAL-XFEL Commissioning Plan ver. 1.1, August 2015 PAL-XFEL Beam Dynamics Group

Commissioning Milestones and Schedule PAL-XFEL Commissioning Plan2 Second milestone of XFEL commissioning (December 2016):  Hard X-ray 0.1 nm SASE with 10 GeV beam  Soft X-ray 3 nm SASE  200 pC, 20 pC  Demo experiments  Repetition rate 10 Hz First milestone of XFEL commissioning (June 2016):  0.25 nm SASE radiation with 6 GeV electron beam  6 GeV beam at linac end (Gun&L0: 100% gradient; L1, L2: 80%; L3a, L3b, L4: 60%)  Repetition rate 10 Hz  Relaxed beam parameters  200 pC is nominal, but 100 pC or lower bunch charge is an option  Gun drive laser with a Gaussian longitudinal profile  Less peak current (weaker bunch compression) for weaker collective effects SONDJFMAMJJASOND Injector install in XFEL, S&A Linac component install, S&A Undulator component install, S&A Injector commissioning Linac RF conditioning (10 Hz) Linac beam commissioning FEL commissioning Maintenance 6 GeV 10 GeV

Layout (for Commissioning Phase 1) PAL-XFEL Commissioning Plan3 injector undulator linac beam transportation line X

Abbreviations L0, L1, L2, L3, L4: S-band linac section ‘0, 1, 2, 3, 4’ LH: Laser Heater BC: Bunch Compressor BD: Beam Dynamics RF: RF DC: Diagnostics and control VC: Vacuum IN: Injector LS: Laser ID: Insertion Device BI: Beamline Instrumentation RS: Radiation Safety US: Utilities Services SAE: SA Engineering PAL-XFEL Commissioning Plan4

Check List before Beam Commissioning Accelerator components installed and aligned <100  m (SAE) Magnet field measured and cooling tested before install, magnet power supplies stability tested (ID) – Polarity check in the tunnel (ID, BD) Laser spot position in place for the gun and laser heater, shutters & movers check, profiles measure (LS) Commissioning of control system (DC) – Moveable components in the beamline movement tested and fully extracted (DC, BD) – Gun solenoid and X-band cavity micromovers tested (BD) – Movers of BCs and collimators tested (ID, BD) Commissioning of timing system (DC) – Rough RF to reference trigger synch using SSA output (RF) Diagnostics lab-tested, installed and commissioned without beam (DC) Water cooling system tested (US) Vacuum level ~ mbar at gun section, ~10 -6 mbar at L0 and downstream, valves and gauges tested (VC) Machine interlock system tested (DC) RF conditioning of all high power RF components at 10 Hz (RF) RF stability checked (RF) Radiation safety system (RS) * All check sheets collected and confirmed (BD) PAL-XFEL Commissioning Plan5

Injector – Gun Gun commissioning – Machine parameter table ready (BD) – Dark current check using gun screen (IN, BD, RF, DC) – Timing between RF and laser (IN, BD, RF, LS, DC) – Production of first electron beam, bunch charge 200 pC (or 100 pC) (IN, BD, DC) – Beam based check of diagnostic components, screens, ICT, BPMs, BAM (IN, DC, BD) – Drive laser alignment, stabilization Laser position alignment using gun phase scan and gun screen (IN, BD) Bunch charge stability < 1%, feedback (LS) – Basic (beam shape, energy) characterization Check if e-beam shape is round and longitudinal profile is Gaussian (BD, LS) Beam energy ~ 5.6 MeV at BAS_gun (BD, RF) – Beam-based gun solenoid alignment using micro-mover and gun screen (BD) – Long-term and short-term stability of cooling, RF, bunch charge check (BD) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan6

Injector – L0 & Laser Heater L0 commissioning – Timing between RF and e-beam (BD, RF, DC) – Beam based check of diagnostic components (DC, BD) – Beam transportation to BAS_0 (BD) – RF amplitude & phase setting as designed using BAS0, beam energy >120 MeV (BD, RF) – Beam based alignment (BD, DC) – Radiation safety (BD, RS) Laser heater commissioning – Beam path check with laser heater chicane on/off (BD) – Position synch between e-beam and IR using screens (BD, LS, DC) – Timing synch between undulator radiation and IR using photodiode and oscilloscope (BD, LS) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan7 Injector parameterPhase IPhase II Bunch charge100 ~ 200 pC200 pC Beam energy120 ~ 140 MeV130 ~ 140 MeV Longitudinal laser shapeGaussianGaussian or flat-top Projected transverse emittance< 1 mm mrad< 0.8 mm mrad Slice transverse emittance< 0.5 mm mrad< 0.4 mm mrad Bunch length in fwhm~5 ps

Linac – L1, X-band L1 commissioning – Beam transportation to BAS_1 with XB off and BC1 chicane by-pass (BD) – Beam based check of diagnostic components (DC, BD) – Timing between RF and beam (BD, RF) – Acc gradient >18 MV/m, 60 MW from klystron (RF) – RF phase setting as designed using BAS_1, beam energy ~350 MeV with X-band off (BD, RF) – Beam based alignment (BD) – Radiation safety (BD, RS) XB commissioning – Beam transportation to BAS_1 with chicane by-pass (BD) – Beam based check of diagnostic components, BAS_1 screen, deflector (BD, DC, RF) – RF phase setting as designed using BAS_1, beam energy ~328 MeV with X-band on (BD, RF) – Amplitude and phase dependence of linearization measurement (BD) – Minimizing the transverse wakefield effect of XB cavity using the micromover (BD) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan8

Linac – BC1 BC1 commissioning – Beam based check of diagnostic components (DC, BD) – Beam based alignment: Orbit correction for dispersion free (BD) – Beam characterization (emittance) with BC1 as bypass (BD) – Compression factor characterization using deflector & BAS1 (BD) – Beam characterization with BC1 on Projected emittance / Slice emittance (BD) Bunch length / Energy spread (BD, DC) Arrival time (DC) – BC1 collimator commissioning (BD, RS) – Stability check using diagnostics Bunch length stability (DC, BD, RF) Beam arrival time stability (DC, BD, RF) Beam pointing stability (BD) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan9

Linac – L2 L2 commissioning – Acc gradient > 12 MV/m, ~55 MW from klystron (RF) – Beam transportation to the dump downstream BC2 (BD) – Beam based check of diagnostic components (DC, BD) – Timing between RF and e-beam (BD, RF, DC) – RF phase setting as designed using BAS2 (BD, RF) Beam energy ~ 1.8 GeV – Beam based alignment (BD) – Check list Energy stability (BD) Beam arrival time stability (BD, DC) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan10

Linac – BC2 BC2 commissioning (Not in operation during Commissioning Phase I) – Beam based check of diagnostic components (DC, BD) – Beam based alignment: Orbit correction for dispersion free (BD) – Compression factor characterization using the deflector & bend downstream of BC3 (BD) – Beam characterization Bunch length / Energy spread (DC, BD) Arrival time (DC, BD) – BC2 collimator commissioning (BD) – Check list Bunch length stability (BD, DC) Beam arrival time stability (BD, DC) Beam pointing stability (BD) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan11

Linac – L3 L3 (L3a & L3b) commissioning – Acc gradient > 12 MV/m, ~55 MW from klystron (RF) – Beam transportation to the dump downstream BC3 – Beam based check of diagnostic components – Timing between RF and e-beam (BD, RF, DC) – RF phase setting as designed using BAS2 and BC3_H (BD, RF) – Beam based alignment – Check list Beam energy >2.35 GeV (BD, RF) Energy stability (BD, DC, RF) Beam arrival time stability (BD, DC, RF) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan12

Linac – BC3 BC3 commissioning – Beam based check of diagnostic components (DC, BD) – Beam based alignment: Orbit correction for dispersion free (BD) – Compression factor characterization using the deflector & BAS3H (BD) – Beam characterization with BC3 on Bunch length / Energy spread (BD, DC) Arrival time (DC, BD) – BC3 collimator commissioning (BD) – Check list Bunch length stability (DC, BD, RF) Beam arrival time stability (DC, BD. RF) Beam pointing stability (BD) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan13

Linac – L4 L4 commissioning – Acc gradient > 12 MV/m, ~55 MW from klystron (RF) – Beam transportation up to linac end (BD) – Beam based check of diagnostic components (DC, BD) – Timing between RF and e-beam (BD, RF, DC) – RF phase setting as designed using BAS3H (BD) – Beam based alignment (BD) – L4 collimator commissioning (BD) – Check list Beam energy ~6 GeV, max 2 RF stations can be off (RF, BD) Energy stability < 0.05% (BD, DC) Beam arrival time stability < 150 fs (BD, DC) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan14

Linac – BT Line Beam transportation line – Beam transportation to undulator entrance (BD) – Beam based check of diagnostic components, screen, BPM, wire scanner (DC, BD) – Beam based alignment: Dispersion optimization (BD) – Energy collimator commissioning (BD, RS) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan15 Phase IPhase II Bunch charge100 pC ~ 200 pC~200 pC Beam energy~6 GeV10 GeV Longitudinal laser shapeGaussianGaussian or flat-top Projected transverse emittance< 2 mm mrad< 1.4 mm mrad Slice transverse emittance< 0.6 mm mrad< 0.5 mm mrad Peak current~2 kA or less~3 kA FEL performance (Ming Xie) Saturation length~60 m at 0.25 nm~60 m at 0.1 nm FEL power~5 GW at 0.25 nm~14 GW at 0.1 nm

Undulator – Pre-beam Pre-beam commissioning – Undulator & phase shifter field measurement, control test (ID) – Undulator, phase shifter, quadrupole mover, cavity BPM mover check – Vacuum check – Performance test of components cavity BPM (DC) magnets, MPS (ID) photon diagnostics (BI) – Machine protection system tested (BD, DC, RS) – Radiation safety system (RS) PAL-XFEL Commissioning Plan16

Undulator – Phase I Undulator commissioning – Transportation to the main dump with undulator gap open (BD) – Beam based diagnostics check, cavity BPM and screen (BD, DC) – BBA of quadrupoles (BD, DC) – Undulator & phase shifter steering table for variable gap (BD, ID) – Beam based undulator alignment (BD, ID, BI) One-by-one undulator alignment using spontaneous radiation and corrector & air coil Iteration of quadrupoles alignment – Beam based undulator (relative) K-value measurement (BD, ID, BI) – Beam based phase shifter tuning (BD, ID, BI) – Set to the design values for the undulators and phase shifters (BD) – First lasing at 0.3 nm (BD) – SASE optimization/characterization Injection orbit optimization (BD) Phase shifter optimization (BD, ID) Compression ratio optimization at BCs (BD) FEL power Vs. laser heater setting (BD, LS) Saturation length measurement (BD) Wavelength tuning with undulator gap (BD, ID) – Radiation safety (BD, RS) PAL-XFEL Commissioning Plan17