1. S2E in LCLS Linac M. Borland, Lyncean Technologies, P. Emma, C. Limborg, SLAC

2. L = 6 m L = 9 m  rf =  38° L = 330 m  rf =  43° L = 550 m  rf =  10° BC-1 L = 6 m R 56 =  36 mm BC-2 L = 22 m R 56 =  22 mm DL-2 R 56 = 0 DL-1 R 56  0 undulator L = 120 m 6 MeV  z  0.83 mm    0.1 % 150 MeV  z  0.83 mm    0.10 % 250 MeV  z  0.19 mm    1.8 % 4.54 GeV  z  0.022 mm    0.76 % 14.35 GeV  z  0.022 mm    0.01 %...existing linac L0 rf gun L3L1 X Lh L =0.6 m  rf =  L2 LCLS

3. Nominal LCLS Optics…

4. LCLS Start-to-End Tracking Simulations  Track entire machine to evaluate beam brightness & FEL  Track machine many times with jitter to test stability budget  See C. Limborg talk for injector  See Fawley, Reiche talks for FEL ParmelaParmelaElegantElegantGenesisGenesis space-charge compression, wakes, CSR, … SASE FEL with wakes LCLS

5. Initial Beam from Parmela Tracking 1 nC 10-psec FWHM 0.7-ps rise/fall 120 MV/m gun  therm  0.3  m 150 MeV 2  10 5 to 2  10 6 macro-particles x, y  x,y < 1  m  x  y z,  E/E

6. Sliced e- Beam to Evaluate FEL (  z  0.7 mm) I pk  x,y E/EE/EE/EE/E

7.  mismatch variation slice 4D centroid osc. amplitude centroidmatch FEL wavelength

8. see S. Reiche, B. Fawley talks… ‘Ming Xie method’ FEL parametergain lengthFEL power

9. X-band X-X-X-X- LCLS. LCLS Longitudinal Jitter Tolerance Budget note, Elegant simulations use 0.5 ps rms

10.  z /  z0  12.5%  /    0.1%  /  0  8.6%  E /  E   0.01%  t  rms  125 fs  t fw /t fw  12.5% 2D tracking used to develop tolerance budget

11. Now add component transverse misalignments… Misaligned randomly in x and y:  All quadrupoles: 300  m rms  All rf structures: 300  m rms  All BPMs:300  m rms Misaligned randomly in x and y:  All quadrupoles: 300  m rms  All rf structures: 300  m rms  All BPMs:300  m rms Transverse wakefields induce projected emittance growth and couple charge jitter to emittance jitter

12. x-y screen trajectory before steering Misaligned randomly in x and y:  All quadrupoles: 300  m rms  All rf structures: 300  m rms  All BPMs:300  m rms Misaligned randomly in x and y:  All quadrupoles: 300  m rms  All rf structures: 300  m rms  All BPMs:300  m rms  x  10000  m

13. after Steered using Elegant’s ‘global’ algorithm  x  5  m  y  2  m  x  5  m  y  2  m trajectory after steering

14. after Now let Elegant optimize both x and y emittances with two x- and two y-steering coils (pairs separated by    /2) steering coils  x  1.02  m  y  1.09  m  x  1.02  m  y  1.09  m

15. M. Borland optimized 100 random seeds…  /   20% (projected)

16.  x (  m) x-position of feedback set-point (  m) Real Emittance Minimization Using Trajectory ‘Bumps’ in SPPS ~10 minutes (Ne  3.5 nC,  z  1 mm) H. Schlarb, P. Emma

17. Now run 200 S2E simulations, including Genesis runs, but with a distorted and ‘emittance-tuned’ trajectory… M. Borland, PE, J. Lewellen, C. Limborg, M. Woodley SC-wiggler is ON

18.  I   3.91 kA, rms  10%  x   2.29  m, rms  5%  E   14.36 GeV, rms  0.04%  y   0.93  m, rms  4% projected x-emittance e  energy projected y-emittance peak current

19.  x  s  0.76  m, rms  2%  y  s  0.67  m, rms  2% sliced x-emittance sliced y-emittance bunch arrival time  t   0, rms  49 fs  E  E   7  10  5, rms  0.8  10  5 sliced energy spread

20. x-position  x   0, rms  9  m (30%  x )  y   0, rms  1.5  m y-position x-angle  x   0, rms  0.55  rad  y   0, rms  0.21  rad y-angle mean values set to zero for Genesis runs

21. wavelength  r   1.5 Å, rms  0.09  gain length  L g   ? m, rms  5%  P   4 GW, rms  25% ??? Gain length  L g   4.1 m, rms  5 

22.  Fairly realistic simulations with jitter demonstrate tight, but achievable tolerances – SPPS experience very helpful  Transverse wakefields are correctable – not a major issue (lower charge, shorter linac, and shorter bunch vs. SLC)  LCLS still deciding on SC-wiggler at BC2, or laser system at injector (as proposed at DESY for TTF-2; Saldin et al.)  LCLS entering engineering stage – detailed design must be ‘nailed’ down very soon (CD-2b in March 2004) Final Comments* * Special thanks to M. Borland: working for free!

23. initial modulation period prior to BC1 CSR gain (1D-model) in LCLS without wakefield or long. space-charge SC-wig ON SC-wig OFF see Z. Huang talk Tuesday