Magnetic Measurements For The LCLS Undulator System Zack

Magnetic Measurements For The LCLS Undulator System Zack Wolf, Yurii Levashov, Achim Weidemann, Seva Kaplounenko, Scott Jansson, Ralph Colon, Dave Jensen Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 1 wolf@slac. stanford. edu

Introduction The LCLS will consist of 33 undulator segments. The last 1/3 of the linac is used to produce the electron beam. Some Parameters: Ebeam = 13. 64 Gev λr = 1. 5 Å Planar permanent magnet undulators Nd Fe B permanent magnets λu = 30 mm Gap = 6. 8 mm Tapered gap, 4. 5 mrad Bfirst = 1. 249 T, tapered, nominal field, first undulator Kfirst = 3. 5, tapered, each undulator has its own K 226 poles per segment Each segment is 3. 4 m long Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 2 wolf@slac. stanford. edu

LCLS Location J. Galayda Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 3 wolf@slac. stanford. edu

Schedule Drive-Laser Commissioning Drive-Laser Installed LTU/und. Install LTU/und. hall “ready” Controls Checkout First Spont. Light A SOND J FMAM J J 2006 2007 2008 Gun/Inj. /BC 1 Install (8/21 – 2/20) Gun/Inj. /BC 1 Commissioning linac/BC 2 Install Dave Schultz Feb 7, 2007 LCLS Magnetic Measurements Inj. /Linac/BC 2 Commissioning LTU/und. Commissioning Zachary Wolf 4 wolf@slac. stanford. edu

Undulator Tuning Magnetic Measurement Facility Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 5 wolf@slac. stanford. edu

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 Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 6 wolf@slac. stanford. edu

Undulator Movements In MMF Tuning Time: about 4 weeks 1 Week, Fine Tuning 1 Week, Rough Tuning 1 Week, Come to 20 C <1 Week, Finish Fiducialization Peak Throughput: 1 undulator per week Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 7 wolf@slac. stanford. edu

MMF Temperature Achim Weidemann In general, the system meets stability requirements Time history at the Kugler bench Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 8 wolf@slac. stanford. edu

Rough Tuning Bench Components Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 9 wolf@slac. stanford. edu

Rough Tuning Bench Reference Pole Undulator Cam Movers Zero Gauss Chamber Cable Handling Bench Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 10 wolf@slac. stanford. edu

Capacitive Sensor Alignment Performance Undulator mechanically aligned to bench in 15 minutes Yurii Levashov Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 11 wolf@slac. stanford. edu

Scans Begin And End In A Zero Gauss Chamber Beginning zero field measurement Ending zero field measurement Senis Hall probe Zero Offset Correction Assume linear offset dependence on time Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 12 wolf@slac. stanford. edu

Gap Shims Tapered Shim ANL TB-48 Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 13 wolf@slac. stanford. edu

X Trajectory Shims Isaac Vasserman’s Ideas ANL/APS/TB-48 § 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 § Developed software to automate shim placement LCLS-TN-04 -7 Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 14 wolf@slac. stanford. edu

Y Trajectory Shims Bx Shim New Design Smaller external fields Uniform Bx field in gap Old Shim Design Inconel Steel Spot weld Yurii Levashov Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 15 wolf@slac. stanford. edu

Straighten X And Y Trajectories Measured X Trajectory Calculate Shims Modeled X Traj With Calc Shims Measured X Traj After Calc Shims Applied The Shimming Is Automated Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 16 wolf@slac. stanford. edu

Phase Shims LCLS-TN-04 -7 ANL/APS/TB-48 § Measure By with a Hall probe § Calculate phase error § Calculate shims to correct error § Apply shims, repeat § We don’t have shims to strengthen a magnet, only weaken § Must locally reduce the gap to increase phase shift § Developed software to automate shim placement Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 17 wolf@slac. stanford. edu

Rough Tuning Test Plan Achim Weidemann 1) Place undulator Use kinematic mount 2) Mechanically align to test stand Optical alignment check, use capacitive sensors and cam movers 3) Magnetically align Hall probe to undulator Move Hall probe in x and y to magnetic center 4) Rough tuning Tune x and y trajectories, anticipate magnetic shield 5) Adjust gap Measure K, adjust gap to set K to required value for that undulator 6) Check alignment Alignment may have changed from gap adjustment 7) Rough tuning Anticipate magnetic shield 8) Add magnetic shield 9) Check tuning Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 18 wolf@slac. stanford. edu

Each Undulator Has Its Own K Value From Heinz-Dieter Nuhn Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 19 wolf@slac. stanford. edu

Fine Tuning Bench Components Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 20 wolf@slac. stanford. edu

Fine Tuning Bench Undulator With Magnetic Shield Cable Handling Cam Movers Kugler Bench Steel Girder And Stands Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 21 wolf@slac. stanford. edu

Kugler Bench Performance Measurements by Georg Gassner X Y straightness spec: < 14 μm Pitch and yaw spec: < 4. 2 μrad Specs met in long block region Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 22 wolf@slac. stanford. edu

Coils For Fine Tuning Bench Bx, By One Undulator Period Long Coils Short Coil Zero Gauss Chamber I 1 I 2 Dave Jensen Field Integral Coil Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 23 wolf@slac. stanford. edu

Fine Tuning Test Plan Yurii Levashov 1) Place undulator Use kinematic mount, use steel girder and stands, shield on 2) Mechanically align to test stand Optical alignment check, use capacitive sensors and cam movers 3) Magnetically align Hall probe to undulator Move Hall probe in x and y to magnetic center 4) Determine the tuning axis Move in x to where K has the required value 5) Tuning Tune x and y trajectories, phase 6) Add phase matching shims 7) Adjust field integrals Use long coil, I 1 and I 2 for both Bx and By 8) Adjust field uniformity Add quadrupole and sextupole shims as necessary 9) Final checks before gluing shims Check x and y trajectory, phase matching, field integrals, uniformity Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 24 wolf@slac. stanford. edu

Fine Tuning Test Plan (cont. ) 10) Glue shims in place Remove y trajectory, quadrupole, sextupole, and phase shims, apply glue, replace 11) Check the gap Make sure no parts of a shim protrude into the gap 12) Check for errors while gluing shims Check x and y trajectories, phase, I 1 and I 2 of Bx and By, uniformity 13) Map Bx and By in the retracted position 14) Final results data set Measure Bx and By at x = -6, -5, …, 6 mm, y = -0. 2, -0. 08, 0. 2 mm, calculate field integrals vs z, 65 scans 15) Find the x position, y=0, where K has the required value 16) Add fiducialization magnets to both ends Measure offsets from beam axis to the center of the fiducialization magnets 17) Rough fiducialization using alignment equipment 18) Measure roll on flats at each undulator end 19) Move undulator to CMM, finish fiducialization Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 25 wolf@slac. stanford. edu

Fiducialization, Determine K vs X K K 0 X Set the probe position to give the nominal K value. Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 26 wolf@slac. stanford. edu

Fiducialization Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 27 wolf@slac. stanford. edu

Hall Probe Calibration Water NMR Chiller For probe temperature Magnet HP 3458 Metrolab NMR Seva Kaplounenko Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 28 wolf@slac. stanford. edu

Schedule Robert Ruland Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 29 wolf@slac. stanford. edu

Quadrupole Fiducialization System LCLS-TN-05 -11 Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 30 wolf@slac. stanford. edu

Quadrupole Fiducialization Vibrating Wire Technique Move wire until the vibration stops: Quadrupole Center Force On Wire A. Temnykh, NIM A 399 (1997) 185. Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 31 wolf@slac. stanford. edu

Detector Signal vs Quad Position Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 32 wolf@slac. stanford. edu

Pitch and Yaw Measurements Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 33 wolf@slac. stanford. edu

Quadrupole Fiducialization Schematic System Overview Wire Vibration Sensor Wire Finder Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 34 wolf@slac. stanford. edu

Conclusion • MMF construction is complete, temperature stability and set point accuracy requirements have been met • The rough tuning bench is complete • The Hall probe calibration system is complete • The fine tuning bench has all components complete. A stage is being repaired for the long coil system. Afterward, the bench will be complete. • The software is complete. Some automation work and improvements are still being done. • Mechanical alignment takes about 15 minutes. • The fine tuning bench construction meets all specifications. • The expected throughput is one undulator per week. Each undulator, however, spends about 4 weeks in the MMF. • One reference undulator gets re-measured every fourth undulator. • We have begun production undulator tuning. Feb 7, 2007 LCLS Magnetic Measurements Zachary Wolf 35 wolf@slac. stanford. edu