S2E in S2E in LCLSLCLS Linac Linac

M. Borland, M. Borland, Lyncean Technologies,Lyncean Technologies,P. Emma, C. Limborg, P. Emma, C. Limborg, SLACSLAC

L = 6 m L = 9 mrf = 38°

L = 330 mrf = 43°

L = 550 mrf = 10°

BC-1L = 6 m

R56= 36 mm

BC-2L = 22 m

R56= 22 mm DL-2R56 = 0

DL-1R56 0

undulatorL = 120 m

6 MeVz 0.83 mm 0.1 %

150 MeVz 0.83 mm 0.10 %

250 MeVz 0.19 mm 1.8 %

4.54 GeVz 0.022 mm 0.76 %

14.35 GeVz 0.022 mm 0.01 %

...existing linac

L0

rfgun

L3L1 X

LhL =0.6 mrf=

L2

LCLSLCLS

Nominal Nominal LCLSLCLS Optics… Optics…

LCLSLCLS Start-to-End Tracking Simulations Start-to-End Tracking Simulations

Track entire machine to evaluate beam Track entire machine to evaluate beam brightness & FELbrightness & FEL

Track machine many times with jitter to test Track machine many times with jitter to test stability budgetstability budget

See C. Limborg talk for injectorSee C. Limborg talk for injector See Fawley, Reiche talks for FELSee Fawley, Reiche talks for FEL

ParmelaParmelaParmelaParmela ElegantElegantElegantElegant GenesisGenesisGenesisGenesis

space-chargespace-charge compression, wakes, CSR, …compression, wakes, CSR, … SASE FEL with wakesSASE FEL with wakes

LCLSLCLS

Initial Beam from Initial Beam from ParmelaParmela Tracking Tracking

1 nC1 nC10-psec 10-psec FWHMFWHM0.7-ps rise/fall0.7-ps rise/fall120 MV/m gun120 MV/m gunthermtherm 0.3 0.3

mm150 MeV150 MeV22101055 to 2 to 2101066

macro-particlesmacro-particles

x, yx, y

xx,,yy < 1 < 1 mmxx

yy

z, z, E/EE/E

Sliced Sliced ee- Beam to Evaluate FEL (- Beam to Evaluate FEL (zz 0.7 0.7 mmm)m)

IIpkpkxx,,yy EE//EE

mismatch variationmismatch variation

slice 4D centroid osc. amplitudeslice 4D centroid osc. amplitude

centroid match FEL wavelength

see S. Reiche, B. Fawley talks…see S. Reiche, B. Fawley talks…

‘‘Ming Xie method’Ming Xie method’

FEL parameter gain length FEL power

X-bandX-band XX--

LCLS.LCLS.

LCLS Longitudinal Jitter Tolerance BudgetLCLS Longitudinal Jitter Tolerance Budget

note, note, ElegantElegant simulations simulations use 0.5 ps use 0.5 ps rmsrms

zz//zz00 12.5% 12.5%

// 0.1% 0.1%

//00 8.6% 8.6%

EE//EE 0.01% 0.01%

ttrmsrms 125 fs 125 fs

ttfwfw//ttfwfw 12.5% 12.5%

2D2D tracking tracking used to used to develop develop

tolerance tolerance budgetbudget

Now add component transverse misalignments…Now add component transverse misalignments…

Misaligned randomly in Misaligned randomly in xx and and yy:: All quadrupoles: All quadrupoles: 300 300 m rmsm rms All rf structures: All rf structures: 300 300 m rmsm rms All BPMs:All BPMs: 300 300 m rmsm rms

Misaligned randomly in Misaligned randomly in xx and and yy:: All quadrupoles: All quadrupoles: 300 300 m rmsm rms All rf structures: All rf structures: 300 300 m rmsm rms All BPMs:All BPMs: 300 300 m rmsm rms

Transverse wakefields induce projected emittance growth and couple charge jitter to

emittance jitter

xx--yy screen screen

trajectory trajectory beforebefore steering steering

Misaligned randomly in Misaligned randomly in xx and and yy:: All quadrupoles: All quadrupoles: 300 300 m rmsm rms All rf structures: All rf structures: 300 300 m rmsm rms All BPMs:All BPMs: 300 300 m rmsm rms

Misaligned randomly in Misaligned randomly in xx and and yy:: All quadrupoles: All quadrupoles: 300 300 m rmsm rms All rf structures: All rf structures: 300 300 m rmsm rms All BPMs:All BPMs: 300 300 m rmsm rms

xx 10000 10000 mm

afterafter

Steered using Steered using ElegantElegant’s ‘global’ ’s ‘global’ algorithmalgorithm

Steered using Steered using ElegantElegant’s ‘global’ ’s ‘global’ algorithmalgorithm

xx 5 5 mm

yy 2 2 mm

xx 5 5 mm

yy 2 2 mm

trajectory trajectory afterafter steering steering

afterafter

Now let Now let ElegantElegant optimize both optimize both xx and and yy emittances with emittances with two two x-x- and two and two y-y-steering coils steering coils (pairs separated (pairs separated by by /2)/2)

Now let Now let ElegantElegant optimize both optimize both xx and and yy emittances with emittances with two two x-x- and two and two y-y-steering coils steering coils (pairs separated (pairs separated by by /2)/2)

steering coilssteering coils

xx 1.02 1.02

mmyy 1.09 1.09

mm

xx 1.02 1.02

mmyy 1.09 1.09

mm

M. Borland optimized 100 random seeds…M. Borland optimized 100 random seeds…

// 20% (projected) 20% (projected)

xx ( (

m)

m)

xx-position of feedback set-point (-position of feedback set-point (m)m)

Real Emittance Minimization Using Trajectory ‘Bumps’ in SPPSReal Emittance Minimization Using Trajectory ‘Bumps’ in SPPS

~10 minutes~10 minutes

((NeNe 3.5 nC, 3.5 nC, zz 1 mm) 1 mm)

H. Schlarb, H. Schlarb, P. EmmaP. Emma

Now run 200 Now run 200 S2ES2E simulations, including simulations, including GenesisGenesis runs, runs, but with a distorted and ‘emittance-tuned’ trajectory… but with a distorted and ‘emittance-tuned’ trajectory…

M. Borland,M. Borland,PE,PE,

J. Lewellen,J. Lewellen,C. Limborg,C. Limborg,M. WoodleyM. Woodley

SC-wiggler SC-wiggler is ONis ON

II 3.91 kA, rms 3.91 kA, rms 10% 10% xx 2.29 2.29 m, rms m, rms 5% 5%

EE 14.36 GeV, rms 14.36 GeV, rms 0.04% 0.04% yy 0.93 0.93 m, rms m, rms 4% 4%

projected projected xx-emittance-emittance

ee energy energy

projected projected yy-emittance-emittance

peak currentpeak current

xxss 0.76 0.76 m, rms m, rms 2% 2%

yyss 0.67 0.67 m, rms m, rms 2% 2%

sliced sliced xx-emittance-emittance

sliced sliced yy-emittance-emittance

bunch arrival timebunch arrival timett 0, rms 0, rms 49 fs 49 fs

EEEE 7 7101055, rms , rms 0.8 0.8101055

sliced energy spreadsliced energy spread

xx-position-positionxx 0, rms 0, rms 9 9 m (30% m (30% xx))

yy 0, rms 0, rms 1.5 1.5 mmyy-position-position

xx-angle-anglexx 0, rms 0, rms 0.55 0.55 radrad

yy 0, rms 0, rms 0.21 0.21 radradyy-angle-angle

mean mean values values set to set to

zero for zero for Genesis Genesis

runsruns

wavelengthwavelength

rr 1.5 1.5 ÅÅ, rms , rms 0.09 0.09

gain lengthgain length

LLgg ? m, rms ? m, rms 5% 5% PP 4 GW, rms 4 GW, rms 25% ??? 25% ???

Gain lengthGain length

LLgg 4.1 m, rms 4.1 m, rms 5 5

Fairly realistic simulations with jitter demonstrate tight, but Fairly realistic simulations with jitter demonstrate tight, but achievable tolerances – achievable tolerances – SPPSSPPS experience very helpful experience very helpful

Transverse wakefields are correctable – not a major issue Transverse wakefields are correctable – not a major issue (lower charge, shorter linac, and shorter bunch vs. (lower charge, shorter linac, and shorter bunch vs. SLCSLC))

LCLSLCLS still deciding on SC-wiggler at BC2, or laser system at still deciding on SC-wiggler at BC2, or laser system at injector (as proposed at DESY for TTF-2; Saldin injector (as proposed at DESY for TTF-2; Saldin et al.et al.))

LCLSLCLS entering engineering stage – detailed design must be entering engineering stage – detailed design must be ‘nailed’ down very soon (CD-2b in March 2004)‘nailed’ down very soon (CD-2b in March 2004)

Final CommentsFinal Comments**

* Special thanks to M. Borland: working for free!* Special thanks to M. Borland: working for free!

initial modulation period prior to BC1initial modulation period prior to BC1

CSR gain (1D-model) in CSR gain (1D-model) in LCLSLCLS without wakefield or long. space-charge without wakefield or long. space-charge

SC-wig ONSC-wig ON

SC-wig OFFSC-wig OFF

see Z. Huang talk Tuesdaysee Z. Huang talk Tuesday