1. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 LCLS Undulator Magnetic Measurements Zack Wolf, Scott Anderson, Ralph Colon, Brendan Dix, Scott Jansson, Dave Jensen, Luis Juarez, Seva Kaplounenko, Yurii Levashov, Wei Wang, Achim Weidemann

2. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 Undulator Tuning, General Approach  Use ANL and DESY experience  Techniques have been developed at ANL and DESY which work very well.  We will use the best of the ANL and DESY measurement techniques as our starting point (both have been very generous in sharing with us).  We need to adapt for production measurements.

3. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 SLAC Magnetic Measurement Facility Floor plan divided into three functional areas Magnetic Measurements (± 0.1º C) Fiducialization and Assembly (± 1º C) Storage (± 2.5º C) Test stand lay-out is driven by requirement to match the Earth Magnetic Field conditions in lab to Undulator Hall, i.e. azimuth and gap orientation need to be identical LCLS-TN-04-1

4. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 MMF Under Construction Photos courtesy of Javier Sevilla Beneficial occupancy in March

5. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 Important Dates MMF Major Construction FinishedFeb. 17, 2006 MMF Beneficial OccupancyMarch 6, 2006 Kugler Bench CompleteApril 15, 2006 Kugler Bench At SLACMay 15, 2006 Kugler Bench Handover To SLACJune 15, 2006 1 st Article Arrives At SLACJuly 2, 2006 MMF Ready For MeasurementsJuly 28, 2006 Production Measurements StartAugust 29, 2006 (Approximate)

6. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 Undulator Measurement Benches ANL BenchDESY Bench LCLS-TN-03-7 Goal: Move probes along a very straight line through the undulator.

7. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 Kugler Bench On order, expected at SLAC May 15, 2006. Ready for use June 15, 2006.

8. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 SLAC Software Development Bench Bench software by Seva Kaplounenko (While we wait on the Kugler bench)

9. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 Undulator Measurement Steps 1)Place undulator 2)Mechanically align undulator to bench 3)Magnetically align Hall probe to undulator 4)Perform any required large gap adjustments and re-align 5)Straighten the X and Y trajectories 6)Minimize phase errors 7)Perform phase matching 8)Determine K vs X, move probe to the X value which gives the specified K 9)Add fiducialization magnets to undulator ends, locate center of fiducialization magnets 10)Move undulator to CMM, finish fiducialization LCLS-TN-03-7

10. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 1) Place Undulator Ben Poling placing the ANL prototype on the SLAC prototype bench 12/9/05.

11. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 1) Place Undulator

12. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 1)Place Undulator Built by Gordon Bowden, Yurii Levashov, Scott Jansson SLAC CAM Movers Brake Motor Harmonic Drive CamPotentiometer Bearing

13. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 2) Mechanically Align to Bench Use Capacitive Sensors We tested capacitive sensors in TTF undulators at DESY Yurii Levashov

14. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 2) Mechanically Align To Bench Undulator aligned to fixed height of reference pole.

15. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 2) Mechanically Align to Bench  Use 6 capacitive sensors on an arm  Gives x, yaw, y, pitch, and roll  Have reference poles at each end  Calibrate sensors with micrometers Previous experience from PEP II and SPEAR III

16. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 3) Magnetically Align Hall Probe By y x  Technique  Every N’th pole, move probe vertically, find minimum  Every N’th pole, move probe horizontally, find midpoint between edges  Plot (x, y) vs z, fit for magnetic alignment x y

17. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 3) Magnetically Align Hall Probe SLAC Measurements

18. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 4) Perform Any Large Gap Adjustments ANL TB-48 Tapered Shim

19. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 5) Straighten X And Y Trajectories LCLS-TN-05-5 Simultaneously measure Bx and By (Hall) and Bx from a coil

20. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 5) Straighten X And Y Trajectories  Apply shims to top and bottom poles  Shims weaken By, don’t cause Bx  Can’t strengthen pole, instead place shims on next pole to reduce deflection in other direction  Developing software to try to automate shim placement ANL/APS/TB-48 LCLS-TN-04-7 ANL/APS/TB-48 Isaac Vasserman’s Ideas

21. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 5) Straighten X And Y Trajectories Measured X Trajectory Calculate Shims Modeled X Traj With Calc Shims Measured X Traj After Calc Shims Applied Automate Shimming, Under Development

22. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 5) Check Hall Probe Field Integrals 150 Turns I1I1 I2I2 Long Coil LCLS-TN-05-22

23. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 5) Earth’s Field LCLS-TN-05-4 We will either a)Measure the field integrals and shim in the tunnel b)Put a mu-metal shield around the undulators (Isaac Vasserman)

24. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 6) Minimize Phase Errors Poles 51 and 52 are 1% too strong.  A magnet which is too strong can cause phase errors.  The trajectory is shifted, but there is no residual slope.  Correct with phase shims. LCLS-TN-04-7 Measured Phase Errors Calculated Shims Under development

25. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 6) Minimize Phase Errors  Measure By with a Hall probe  Calculate phase error  Calculate shims to correct error  Apply shims, repeat  Developing software to automate shim placement ANL/APS/TB-48LCLS-TN-04-7  We don’t have shims to strengthen a magnet, only weaken  Must locally reduce the gap to increase phase shift

26. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 7) Phase Matching Phase Matching Shim Data Entrance: Number of end poles = 5 Measured Phase At The Entrance Poles: (Phase = 0 at the entrance cell boundary.) Pole Number = 1 2 3 4 5 6 Phase (deg) = 393.80 436.28 624.41 811.05 986.83 1157.97 Expected phase at pole number 6 = 1170.00 deg Entrance phase error (from pole 6) = -12.03 deg Entrance phase match shim dimension = 0.0000e+000 m Program provides shim information (under development) pi pi/2 (mod 2pi)

27. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 8) Determine K vs X Sinusoidal Field K X K0K0 Canted Poles K vs X LCLS-TN-04-7 Set the probe position to give the nominal K value. K Shim Data Measured K value = 3.627747 Desired K value = 3.500000 Required field change dB / B = -3.6499e-002 Required gap change dgap = 2.1330e-004 m Beam x motion required dx = 4.7401e-002 m Analysis Program Gives K For Each X Run Calculated Undulator Parameters: Keff = 3.627747 Beff = 1.295076 T Lambda_rad = 1.595811e-010 m X0X0 (prototype) (under development)

28. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 9) Add Fiducialization Magnets Need to relate magnetic field to tooling balls. Attach to undulator ends, measure offsets LCLS-TN-05-10 Yurii Levashov

29. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 10) Move to CMM, Finish Fiducialization Want D D1 : Magnetic Measurement D2 : Calibration D3 : CMM D = D1 + D2 + D3

30. Zack Wolf Undulator Magnetic Measurementswolf@slac.stanford.edu April 11, 2006 Conclusion Our group’s next big magnetic measurement project is the LCLS. A new magnetic measurements lab is being built. We will use Hall probes and coils to tune the undulators. Long coils will check the first and second field integrals. High gradient magnets with well defined centers will be used to fiducialize the undulators. Algorithms are being developed to automate shimming.