Magnetic Measurements For The LCLS Undulator System
description
Transcript of Magnetic Measurements For The LCLS Undulator System
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20071
Magnetic MeasurementsFor The
LCLS Undulator System
Zack Wolf, Yurii Levashov,
Achim Weidemann, Seva Kaplounenko,
Scott Jansson, Ralph Colon, Dave Jensen
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20072
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 Gevλr = 1.5 ÅPlanar permanent magnet undulatorsNd Fe B permanent magnetsλu = 30 mmGap = 6.8 mmTapered gap, 4.5 mradBfirst = 1.249 T, tapered, nominal field, first undulatorKfirst = 3.5, tapered, each undulator has its own K226 poles per segmentEach segment is 3.4 m long
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20074
Schedule
AAAA SSSS OOOO NNNN DDDD JJJJ FFFF MMMM AAAA MMMM JJJJ JJJJ AAAA SSSS OOOO NNNN DDDD JJJJ FFFF MMMM AAAA MMMM JJJJ JJJJ
Drive-Drive-Laser Laser
InstalledInstalled
Drive-Laser Drive-Laser Commissioning Commissioning
Gun/Inj./BC1 Gun/Inj./BC1 Commissioning Commissioning
Gun/Inj./BC1 Gun/Inj./BC1 InstallInstall
(8/21 – 2/20)(8/21 – 2/20) linac/BC2 linac/BC2 Install Install
Inj./Linac/BC2 Inj./Linac/BC2 Commissioning Commissioning
LTU/und. LTU/und. Install Install
2006200620062006 2007200720072007
LTU/und.LTU/und.hall “ready”hall “ready”
ControlsControlsCheckouCheckou
t t
LTU/und. LTU/und. Commissioning Commissioning
First Spont. First Spont. LightLight
2008200820082008
Dave Schultz
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20075
Undulator Tuning
Magnetic Measurement Facility
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20076
Magnetic Measurement Facility
Floor plan divided into three functional areasMagnetic 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
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20077
Undulator Movements In MMF
1 Week, Come to 20 C
1 Week, Rough Tuning
1 Week, Fine Tuning
<1 Week, FinishFiducialization
Peak Throughput: 1 undulator per week
Tuning Time:about 4 weeks
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20078
MMF Temperature
Achim Weidemann
Time history at the Kugler bench
In general, the system meets stability requirements
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 20079
Rough Tuning Bench Components
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200710
Rough Tuning Bench
CamMovers
Cable Handling Bench
UndulatorReference Pole
Zero Gauss Chamber
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200711
Capacitive Sensor Alignment Performance
Undulator mechanically aligned to bench in 15 minutes
Yurii Levashov
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200712
Scans Begin And End In A Zero Gauss Chamber
Beginningzero fieldmeasurement
Endingzero fieldmeasurement
Senis Hall probe
Zero Offset CorrectionAssume linear offset dependence on time
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200713
Gap Shims
ANL TB-48
Tapered Shim
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200714
X Trajectory Shims
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
ANL/APS/TB-48
LCLS-TN-04-7
ANL/APS/TB-48
Isaac Vasserman’s Ideas
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200715
Y Trajectory Shims
X-field vs. X-position
-0.004
-0.003
-0.002
-0.001
0
0.001
0.002
0.003
0.004
0.015 0.02 0.025 0.03 0.035 0.04
meters
T
Bx ShimNew Design
Smaller external fieldsUniform Bx field in gap
Yurii Levashov
Inconel
SteelSpot weld
OldShim
Design
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200716
Straighten X And Y Trajectories
MeasuredX
Trajectory
CalculateShims
ModeledX TrajWithCalc
Shims
MeasuredX Traj
After CalcShimsApplied
The Shimming Is Automated
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200717
Phase Shims
Measure By with a Hall probe Calculate phase error Calculate shims to correct error Apply shims, repeat
Developed 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
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200718
Rough Tuning Test Plan1) Place undulator
Use kinematic mount2) Mechanically align to test stand
Optical alignment check, use capacitive sensors and cam movers3) Magnetically align Hall probe to undulator
Move Hall probe in x and y to magnetic center4) Rough tuning
Tune x and y trajectories, anticipate magnetic shield5) Adjust gap
Measure K, adjust gap to set K to required value for that undulator6) Check alignment
Alignment may have changed from gap adjustment7) Rough tuning
Anticipate magnetic shield8) Add magnetic shield9) Check tuning
Achim Weidemann
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200719
Each Undulator Has Its Own K Value
From Heinz-Dieter Nuhn
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200720
Fine Tuning Bench Components
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200721
Fine Tuning Bench
Kugler Bench
Cable Handling
Steel GirderAnd Stands
Cam Movers
UndulatorWith MagneticShield
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200722
Kugler Bench Performance
Measurements by Georg Gassner
X Y straightness spec: < 14 μmPitch and yaw spec: < 4.2 μrad
Specs met in long block region
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200723
Coils For Fine Tuning Bench
Field Integral Coil
Short Coil Zero Gauss Chamber
Dave Jensen
Bx, By One Undulator Period Long Coils
I1
I2
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200724
Fine Tuning Test Plan1) Place undulator Use kinematic mount, use steel girder and stands, shield on2) Mechanically align to test stand
Optical alignment check, use capacitive sensors and cam movers3) Magnetically align Hall probe to undulator
Move Hall probe in x and y to magnetic center4) Determine the tuning axis Move in x to where K has the required value5) Tuning Tune x and y trajectories, phase6) Add phase matching shims7) Adjust field integrals Use long coil, I1 and I2 for both Bx and By8) Adjust field uniformity Add quadrupole and sextupole shims as necessary9) Final checks before gluing shims Check x and y trajectory, phase, phase matching, field integrals, uniformity
Yurii Levashov
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200725
Fine Tuning Test Plan (cont.)10) Glue shims in place Remove y trajectory, quadrupole, sextupole, and phase shims, apply glue, replace11) Check the gap
Make sure no parts of a shim protrude into the gap12) Check for errors while gluing shims
Check x and y trajectories, phase, I1 and I2 of Bx and By, uniformity13) Map Bx and By in the retracted position14) Final results data set Measure Bx and By at x = -6, -5, …, 6 mm, y = -0.2, -0.08, 0 0.08, 0.2 mm, calculate field integrals vs z, 65 scans15) Find the x position, y=0, where K has the required value16) Add fiducialization magnets to both ends Measure offsets from beam axis to the center of the fiducialization magnets17) Rough fiducialization using alignment equipment18) Measure roll on flats at each undulator end19) Move undulator to CMM, finish fiducialization
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200726
Fiducialization, Determine K vs X
K XK0
K vs X
Set the probe position to give the nominal K value.
X0
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200728
Hall Probe Calibration
SENIS 24-06
-50
-40
-30
-20
-10
0
10
20
30
40
50
-10 -8 -6 -4 -2 0 2 4 6 8 10
Voltage (V)
Fie
ld-0
.2*V
olt
age
(G)
SENIS 24-06
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-10 -8 -6 -4 -2 0 2 4 6 8 10
Voltage (V)
Fie
ld (
T)
ChillerFor probetemperature
Magnet
Water NMR
MetrolabNMR
HP3458
Seva Kaplounenko
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200730
Quadrupole Fiducialization System
LCLS-TN-05-11
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200731
Quadrupole FiducializationVibrating Wire Technique
Force On Wire
Move wire until the vibration stops:Quadrupole Center
A. Temnykh, NIM A 399 (1997) 185.
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200732
Detector Signal vs Quad Position
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200734
Quadrupole FiducializationSchematic System Overview
Wire Vibration Sensor
Wire Finder
Zachary Wolf
LCLS Magnetic Measurements [email protected]
Feb 7, 200735
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.