1. Longitudinal Impedance Budget from LINAC to SASE2 Igor Zagorodnov Beam Dynamics Group Meeting 13.11.06

2. SASE2 SASE1 (W.Decking)

3. Wakefield sources - Resistance of the pipe (r=25mm, L=456m, Aluminium) - Collimators (r=2mm, L=50cm, 4 items, TIMETAL 6-4 ) - Kickers (r=10mm, L=10m, 3 items, R/L  m )

4. Collimator (geometrical wake) Diffractive regime: the geometrical wake repeats the bunch shape

5. TIMETAL 6-4 alloy (Titanium) (E.Schutz MVA) http://www.timet.com/timetal6-4frame.html Collimator (resistive wake) M.Dohlus. TESLA 2001-26, 2001 K.L.F.Bane, G.V.Stupakov, SLAC-PUB-10707, 2004

6. TIMETAL 6-4 alloy (Titanium) Geom.Res.Total Loss8273291156 Spread501359829 Peak-1665-823-2411 Collimator total resistive bunch

7. Aluminium resistivetotal Loss6.67.4 Spread5.96.5 Peak-14.5-15.9 Pipe (resistive+oxid layer+roughness) resistive bunch (T.Wohlenberg)

8. Kicker (geometrical wake) (T.Wohlenberg)

9. Kicker (resistive wake) (T.Wohlenberg)

10. Geom.Res.Total Loss3008941195 Spread182469592 Peak-604-1526-1905 Kicker total resistive bunch

11. Pipe (456m) Collimators (4 items) Kickers (3*10m) Total Loss33594623358411565 Spread2963331517777617 Peak-7248-9645-5714-21636 TOTAL (LINAC to SASE2) collimators pipe bunch kickers

12. Energy spread due to wakefields between LINAC and SASE 2 bunch before SASE2 after LINAC

13. Energy losses between LINAC and SASE2 vs. pipe radius R Spread Loss Peak With oxid layer and roughness Geometrical +resistive

14. undulator pipe (42*5.1m) intersection pipe (41*0.7m) absorbers (41*0.3m items) Total (old geometry)* Loss939586916891.19e41.11e4 Spread16560172314701.95e41.89e4 Peak-33789-3435-4200-4.1e4-4.0e4 TOTAL (SASE2) undulator pipe bunch absorbers pipe in intersection (T.Wohlenberg) * M. Dohlus et al, TESLA-FEL 2005-10

15. Energy spread between LINAC and SASE2 vs. pipe radius R (normalized to the spread in SASE2) Spread total collimators

16. Conclusion Impact on FEL performance? (spectrum from SASE simulations?) Spread total collimators

17. Appendix A. Kick factors of flat and round collimators are equal round flat

18. Appendix A. Kick factors of flat and round collimators are equal round flat =

19. Appendix A. Kick factors of flat and round collimators are equal round flat Kick of the flat collimator is equal to the kick of the round one = = = 0.5

20. Appendix B. XFEL collimator vs. cryomodule

21. b2, mm Kick, V/pC/m 118*10 3 24.5*10 3 32.0*10 3 41.1*10 3 50.7*10 3 25~6.5 For the bunch with sigma=25mkm the kick from the collimator with apperture b 2 =2mm is equal to the kick of ~700 cryomoduoles Emmitance growth?