1. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Beam-Based Alignment with New Parameters Paul Emma, SLAC Oct. 24, 2003 Brief Review of Technique Old Parameters New Parameters Cub Horror Brief Review of Technique Old Parameters New Parameters Cub Horror LCLS

2. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC The Method BPM readings, m i, written as sum of upstream kicks + offset, b i Kicks are sensitive to momentum, p k, while offsets, b i, are not BPM readings, m i, written as sum of upstream kicks + offset, b i Kicks are sensitive to momentum, p k, while offsets, b i, are not s b i > 0  E = 0  E < 0 quad offsets and/or pole errors i th BPM  j  j

3. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Reference line defined by incoming x 0, x 0 launch conditions...The Method 1/p mimimimi offset =  b i (15 GeV/c)  1 (7.0 GeV/c)  1 (4.5 GeV/c)  1 p  linear only if C ij independent of p

4. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Schematic layout ~300  m UNDULATOR (122 m) LINAC best final trajectory steering elements x0x0x0x0 x0x0x0x0 initial incoming launch error Undulator misaligned w.r.t. linac axis with uncorrelated and correlated* (‘random walk’) component permanent magnet quad and undulator poles * suggested by C. Adolphsen BPMsquads

5. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Possible Absolute Trajectory LINAC Beam is launched straight down undulator, with possible inconsequential kink at boundary dispersion generated is insignificant

6. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Input errors used for simulation 0.04 0 4444 100 100 2

7. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Natural Undulator Y-Focusing Now Included Recently included natural focusing in Y-plane No change if included in both simulation and reconstruction Small change if not included in reconstruction (not shown) Thanks to H.-D. Nuhn, S. Reiche, J. Welch Recently included natural focusing in Y-plane No change if included in both simulation and reconstruction Small change if not included in reconstruction (not shown) Thanks to H.-D. Nuhn, S. Reiche, J. Welch

8. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Initial BPM and quad misalignments (w.r.t. linac axis) + Quadrupole positions positions o BPM offsets quad positions BPM offsets Now launch beam through undulator 

9. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Initial trajectory before any correction applied + Quadrupole positions positions o BPM readback e  trajectory e  trajectory ‘real’ trajectory quad positions BPM readings

10. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC After 3 rd pass of BBA with old parameters (14.3 GeV) + Quadrupole positions positions o BPM readback e  trajectory e  trajectory RON (FEL-code) simulation shows L sat increased by <1 gain-length; R. Dejus, N.Vinokurov   300°  x  7  m  y  6  m rms beam size:  28  m

11. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC After 3 rd pass of BBA with new parameters + Quadrupole positions positions o BPM readback e  trajectory e  trajectory   73°  x  2.6  m  y  2.7  m rms beam size:  33  m 14 – 7.0 – 4.5 GeV

12. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Now try 2-times worse initial random misalignments + Quadrupole positions positions o BPM offsets quad positions BPM offsets 2-  m BPM resolution + 100-  m initial BPM & quad offsets +  2-  m mover backlash

13. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC After 3rd pass, new parameters, combined ‘worst case’ 2-  m BPM resolution + 100-  m initial BPM & quad offsets +  2-  m mover backlash   184°  x  4.9  m  y  6.0  m

14. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Run BBA on 25 Random ‘worst case’ Seeds 2-  m BPM resolution + 100-  m initial BPM & quad offsets +  2-  m mover backlash Final X-trajectories Final Y-trajectories

15. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Run BBA on 25 Different Random ‘Worst-Case’ Seeds 2-  m BPM resolution + 100-  m initial BPM & quad offsets +  2-  m mover backlash Final X-mover settings Final Y-mover settings wider mover range at end due to lack of BPMs after undulator

16. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Run BBA on 25 Different Random ‘Worst-Case’ Seeds 2-  m BPM resolution + 100-  m initial BPM & quad offsets +  2-  m mover backlash x,yx,yx,yx,y x & y mover distrib.

17. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Evaluation of BBA Simulation Results (old parameters) Trajectory (BBA & Genesis) P sat and L sat vs BPM res. B. Fawley, H.-D. Nuhn, S. Reiche, PE

18. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Summary BPMs resolve trajectory to <2  m rms BPM readings ‘drift’ <2  m over 1-2 hr (temperature) Quad movers settable to better than  2  m, or small steering coils for final correction BPM readings are not sensitive to variable beam size, etc. Trajectory is stable enough to <20% of beam size (already demonstrated in FFTB) Kerry Wood pitches no-hitter in opener BPMs resolve trajectory to <2  m rms BPM readings ‘drift’ <2  m over 1-2 hr (temperature) Quad movers settable to better than  2  m, or small steering coils for final correction BPM readings are not sensitive to variable beam size, etc. Trajectory is stable enough to <20% of beam size (already demonstrated in FFTB) Kerry Wood pitches no-hitter in opener For new parameters: Alignment can be achieved at adequate level using beam-based technique, given that… LCLS

19. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Reserve Slides Next slides are in reserve for questions

20. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Add 10-  m random BPM offsets and correct trajectory + Quadrupole positions positions o BPM readback e  trajectory e  trajectory   113° (old parameters)

21. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Wait 2 weeks, allow 3 bad BPMs, and 2 moved quads + Quadrupole positions positions o BPM readback e  trajectory e  trajectory   1137° 2 weeks of ‘ATL’ diffusive ground motion 3 BPM offsets drift by 20  m 2 quads moved by 20  m  2 = A·T·L, 2  m at T = 2 wk, L = 3.5 m (old parameters)

22. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC Now correct trajectory with ‘careful’ steering + Quadrupole positions positions o BPM readback e  trajectory e  trajectory   173° Much beyond this level will require repeat iteration of BBA  x  3.5  m  y  4.8  m (old parameters)

23. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC After 3 rd pass, new parameters,  2-  m mover backlash   83°  x  1.8  m  y  4.7  m  2-  m random mover backlash (uniform dist. with FWHM = 4  m)

24. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC After 3 rd pass, new parameters,  4-  m mover backlash   124°  x  2.5  m  y  8.0  m  4-  m random mover backlash (uniform dist. with FWHM = 8  m)

25. Beam-Based Alignment with New Parameters Emma@SLAC.Stanford.edu Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center LCLS Undulator Workshop, Oct. 24, 2003 Paul Emma, SLAC After 3 rd pass BBA, new parameters, 100-  m initial alignment 100-  m initial BPM & quad offsets (uncorrelated)   88°  x  3.6  m  y  2.8  m