1. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 1 Undulator Bench Requirements Zack Wolf SLAC

2. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 2 Introduction  We require a measurement bench to move probes through the undulators.  To purchase the bench, we must determine specifications for it:  Physical characteristics such as the length must be determined.  The quality of the bench performance must be specified.

3. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 3 Measurement System Overview

4. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 4 Example Of A Bench ANL Bench Bench Carriage Drive Air Bearing (Vacuum Load) Stages, Probes Photo courtesy of R. Ruland Horizontal Reference Surface Vertical Reference Surface

5. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 5 Tasks and Measurement Equipment Requirements  Straighten trajectory (Hall probe, coil)  K vs x (Hall probe)  Phase shimming (Hall probe)  First and second field integrals (Hall probe, coil, wire system)  Phase matching (Hall probe, two undulators on bench)  Fiducialization (Add “pointed” magnets, bench flat) Account for all equipment space requirements when specify length.

6. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 6 Bench Dimensions  Length, important  Transverse dimensions, leave up to manufacturer to meet probe motion tolerances, handling requirements, etc.  Shape, need carriage constrained so air bearing can not come free Need to specify length and shape

7. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 7 Bench Length Wire System Phase Matching Specify: 8 m bench

8. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 8 Bench Shape DESY Bench Carriage is captured.

9. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 9 Quality of Bench Construction  Probe position affects the measurement results.  Bench errors affect the probe position.  We must specify the bench errors so the measurements are within tolerance.

10. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 10 Plan to Specify Bench Error Limits Probe Motion Error Bench Error Measurement Error Calculated Undulator Parameter Error Undulator Error After Tuning

11. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 11 Undulator Requirements* Max trajectory walkoff per 10 m: 5 mmMax first field integral: 40 mTmMax second field integral: 50 mTm2Electron phase deviation: 10 degreesRMS magnet error B/B: 0.015 %Max trajectory walkoff per 10 m: 5 mmMax first field integral: 40 mTmMax second field integral: 50 mTm2Electron phase deviation: 10 degreesRMS magnet error B/B: 0.015 % ParameterValueUnits Max trajectory walkoff per 10 m 5m Max first field integral40mTm Max second field integral50mTm 2 Electron phase deviation10degrees RMS magnet error  B/B 0.015% *From the LCLS parameters database on the web.

12. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 12 Measurement Result Error Limits ParameterValueUnits Calc trajectory walkoff in undulator2m Calc trajectory slope at exit8.80x10 -7 Calc trajectory offset at exit1.10x10 -6 m Calc phase deviation10deg Field measurement accuracy0.015%

13. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 13 Probe Motion Errors Need limits on dx, dy, dz, and dp Ideal path Actual path Probe motion errors cause measurement errors which cause errors in calculated undulator parameters

14. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 14 Vertical Probe Motion ByB y (y, z) = B 0 cosh(2py/l u ) sin(2pz/l u ) y By BB yy For  B/B 0 < 0.015 %,  y < 83 mm Take Dy max = 20 mm Vertical probe motion error limit set by field measurement accuracy (LCLS-TN-04-8): (Agrees with fiducialization requirement of 20 μm.)

15. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 15 Horizontal Probe Motion x By BB xx  B/B 0 = -(0.77 1/m)  x For  B/B 0 < 0.015 %,  x < 195 mm Take Dx max = 40 mm (Agrees with fiducialization requirement of 40 μm.) Horizontal probe motion error limit set by field measurement accuracy (LCLS-TN-04-8):

16. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 16 Axial Probe Motion Calculated trajectory offset error places limit  z max = 5.9 mm Take  z max = 3 mm (LCLS-TN-04-8)(Don’t use entire error budget on one error.)

17. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 17 Summary of Probe Motion Requirements ParameterValueUnits Maximum vertical deviation Dy20m Maximum horizontal deviation  x 40m Maximum axial deviation  z 3m Maximum probe angle error8mrad (see LCLS-TN-04-8 for details)

18. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 18 Bench Errors Cause Probe Motion X Deviation (Δx)Y Deviation (Δy)Roll Deviation (Δy) Pitch Deviation (Δy, Δz) Yaw Deviation (Δz)

19. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 19 Summary of Bench Construction Requirements ParameterProbe Motion Quad Limit Units Carriage x deviationDxDx40m Carriage y deviationDyDy14m Carriage roll deviationDyDy14mrad Carriage pitch deviationDy, Dz4.2mrad Carriage yaw deviationDzDz4.2mrad

20. Zack Wolf Undulator Bench Requirementswolf@slac.stanford.edu October 14, 2004 20 Conclusion We request from the vendor 1) An 8 meter long bench, 7 meters of travel 2) Carriage motion with the following specifications ParameterMaxUnits Carriage x deviation40m Carriage y deviation14m Carriage roll deviation14mrad Carriage pitch deviation4.2mrad Carriage yaw deviation4.2mrad 3) Limit switches, brakes, bench non-magnetic, … (see LCLS-TN-04-8 for complete list)