Preliminary Tracking Results through LCLS-II P. Emma et al., Oct. 23, 2013 Thanks to Mark Woodley and Yuri Nosochkov for MAD design work Use Christos Papadopoulos ASTRA run at 100 pC (95 MeV, ‘symmetric’) Run Elegant with 250 k macro-particles (CSR, L-wakes, 2 nd order optics) Send output to FEL simulators (Y. Ding, G. Marcus, J. Wu) – next week? Latest results from M. Venturini (LBNL)

LCLS-II Layout (drawn only approximately to scale)

ASTRA Tracking Results for LCLS-II Injector (NGLS) Christos Papadopoulos (LBNL) Bunch Charge0.1nC UV pulse length (FWHM)33ps Spot diam. On cathode0.77mm Peak Current (95 MeV)12A Compression factor3- Buncher Gradient3.7MV/m Buncher Phase  84.5deg CM01 Grad (cav. 1)10.9MV/m CM01 Grad (cav. 2)3.3 MV/m CM01 Grad (cav. 3-7)15.5 MV/m CM01 Grad (cav. 8, spare)0

Optics across the entire LCLS-II, from exit of the CM01 injector cryo-module (95 MeV) to the start of the SXR undulator at 4 GeV. Mark Woodley, Yuri Nosochkov (SLAC) Elegant Tracking Results for Full LCLS-II (SXR) BC1 BC2

Elegant Tracking: Electron Energy Electron energy across the entire LCLS-II, from exit of the CM01 injector cryo-module (95 MeV) to the start of the SXR undulator at 4 GeV. 4 GeV 95 MeV SXR undulator entrance

Elegant Tracking: Bunch Length & Energy Spread RMS bunch length (blue) and rms relative energy spread (magenta) across LCLS-II, from exit of the CM01 injector cryo-module (95 MeV) to the start of the SXR undulator at 4 GeV. RW-wall wake of 2.4-km bypass line added all at one point here

Before Laser Heater (95 MeV) After Laser Heater (95 MeV) (6 keV rms added) After BC1 (250 MeV) After BC2 (1.6 GeV) At SXR entrance (4 GeV) (includes wake of bypass) CSR

Elegant Tracking: Projected Emittance Hor. (black) and vertical (blue) emittance across LCLS-II, from exit of the CM01 injector cryo-module (95 MeV) to the start of the SXR undulator at 4 GeV. BC2 Dog-Leg 1 Dog-Leg 2 CSR effects not minimized at all yet (see M. Venturini slides next)

Elegant Tracking: Sliced Emittance and Energy Spread 4 GeV at SXR FEL entrance 4 GeV at SXR FEL entrance (heater at 6 keV)  E / E  0.012% (500 keV) rms CSR  x,y  0.3  m

Reduced BC2 |R 56 |, larger HL voltage Settle for 850 A rather than 1 kA Re-matched beam 850 A Recent Studies by Marco Venturini (LBNL)

Emma Version Marco’s Version Emma Version Marco’s Version

Summary We are in reasonable shape for the CDR FEL simulations still needed: SXR SASE & Self-Seeded (G. Marcus) HXR SASE (Y. Ding) HXR Self-Seeded (J. Wu)  -bunching study needed: Analytical estimate (A. Marinelli, Z. Huang) IMPACT study (J. Qiang – later?) Might also try Marco’s latest, if time allows Much more to study/improve after CDR