Preliminary Tracking Results through LCLS-IIP. 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, 2nd 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 Charge 0.1 nCUV pulse length (FWHM) 33 psSpot diam. On cathode 0.77 mmPeak Current (95 MeV) 12 ACompression factor 3 -Buncher Gradient 3.7 MV/mBuncher Phase -84.5 degCM01 Grad (cav. 1) 10.9 MV/mCM01 Grad (cav. 2) 3.3 MV/mCM01 Grad (cav. 3-7) 15.5 MV/mCM01 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 Do

g-Le

g 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)

sE/E 0.012% (500 keV) rms

CSR

gex,y 0.3 mm

• Reduced BC2 |R56|, 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)

m-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