Linac Design and Status P. Emma LCLS DOE Review SC1/SC2 Breakout February 8, 2006

1. Linac Design and StatusP. EmmaLCLS DOE ReviewSC1/SC2 BreakoutFebruary 8, 2006 LCLS

2. Outline • Linac intro. & parameters • Low-charge operation • Project documentation • Commissioning plans • Inj-BC1 commissioning • Trajectory jitter & tolerances • Summary

3. Commission in Jan. 2008 Commission in Jan. 2007 LCLS Accelerator and Compressor Schematic 250 MeV z  0.19 mm   1.6 % 4.30 GeV z  0.022 mm   0.71 % 13.6 GeV z  0.022 mm   0.01 % 6 MeV z  0.83 mm   0.05 % 135 MeV z  0.83 mm   0.10 % Linac-X L =0.6 m rf= -160 Linac-0 L =6 m rf gun L0-a,b Linac-3 L 550 m rf  0° Linac-1 L 9 m rf  -25° Linac-2 L 330 m rf  -41° 25-1a 30-8c 21-3b 24-6d ...existing linac 21-1 b,c,d undulator L =130 m X BC1 L 6 m R56 -39 mm BC2 L 22 m R56 -25 mm DL1 L 12 m R56 0 DL2 L =275 m R56  0 SLAC linac tunnel research yard

4. Low-Charge Option (200 pC) Charge: 1 nC0.2 nC Slice emittance: 1 mm0.8 mm Gun Current: 10030 A (10 ps6.5 ps) Final current:3.4 kA2.0 kA(same Lsat) und. wakes • BC2 CSR De 1/5 • L2 trans. wake De1/16 • Peak current jitter  1/2 • X-ray pulse 85 fs (was 200 fs) • ‘No’ undulatorwakes • PFEL 10 GW, 1012 photons • eng. baseline unchanged • 1-nC still fully supported • Full Elegant and Ginger/Genesis S2E’s completed 1 nC 0.2 nC

5. Project Documentation • Physics Requirements Documents (PRD) • Engineering Requirements Documents (ESD) 31 PRD’s & ESD’s 104 magnet sheets http://www-ssrl.slac.stanford.edu/lcls/internals/documents/prd/ http://www-ssrl.slac.stanford.edu/lcls/linac/specs/

6. Example PRD’s 1.1-006, Magnets 1.1-008, Vibrations 1.1-010, Polarities 1.3-017, Collimators

7. Machine Commissioning Plans • Work in MS-Project • One file/manager per system • Link to milestones and events in Master file Injector-BC1 BC2 LTU-und. install install Dec. ‘05 Sep. ‘07 Dec. ‘07 Mar. ‘08 Dec. ‘06 Aug. ‘06

8. Linac Commissioning Plans

9. Injector Through BC1 Commissioning no laser-heater sE gex,y and slice RF deflector E

10. Injector Through BC1 Commissioning (2) CSR relative bunch length monitor? BC1 sE stopper X-band RF gex,y E slice gey

11. Trajectory Stability – Sources of Jitter(f > 10 Hz; Use feedback for f < 10 Hz) • Steering coil current regulation (121 x, 121 y) • Bend magnet trim coil current reg. (13 x, 2 y) • Misaligned quads/sol’s + current reg. (148 mag’s) • Quad/solenoid mech. vibration (148 mag’s) • CSR kicks with bunch length jitter (BC2, x only) • Transverse wakes and charge jitter (X-band RF) • Drive laser pointing stability Expected Sources of Transverse Jitter

12. Quadrupole Magnet Vibration Existing Linac ‘QE’ Quadrupole Magnets R. Stege, J. Turner, 1994 rubber boot on water pump • 12 quads need rms 500 nm (most new injector quads) • 101 magnets need rms 100 nm (existing linac quads) • 35 quads need rms 50 nm (mostly new LTU quads)

13. CSR-Induced x-Trajectory Jitter 10% bunch length jitter  16% ‘core’ trajectory jitter 1-nC 22 mm 20 mm 18 mm core

14. Trajectory Stability – Tol’s & Expectations System Stability Requirements at f > 10 Hz • Steering coils (30-100 ppM  6% of beam size) • Trim coils (30-100 ppM  2%) • Misaligned quads (Dx 200 mm: 25-100 ppM  6%) • Quad/solenoid vibration (0.05-1 mm required  10%) • CSR kicks (1 nC, Dsz/sz  10%:  ~20%, x-only) • Wakes (Dx 200 mm, DN/N  2%  2%) • Drive laser pointing ( 3%) 0.2 nC is more stable

15. Summary • Linac parameters are well defined and stable • Project documents describe requirements • Detailed commissioning plans exist and are being further advanced • Studies finished on collimation, machine tune-up, and expected trajectory stability • Longitudinal feedback needed (see J. Wu) • Linac through BC1 is ready for construction in Fall ’06 and commissioning in Dec. ’06.