lcls undulator magnetic measurements
DESCRIPTION
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. Undulator Tuning, General Approach. Use ANL and DESY experience - PowerPoint PPT PresentationTRANSCRIPT
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
LCLS UndulatorMagnetic Measurements
Zack Wolf,
Scott Anderson, Ralph Colon, Brendan Dix, Scott Jansson, Dave Jensen, Luis Juarez,
Seva Kaplounenko, Yurii Levashov,
Wei Wang, Achim Weidemann
Zack Wolf
Undulator Magnetic Measurements [email protected]
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.
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
SLAC 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
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
MMF Under Construction
Photos courtesy of Javier SevillaBeneficial occupancy in March
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
Important Dates
MMF Major Construction Finished Feb. 17, 2006MMF Beneficial Occupancy March 6, 2006Kugler Bench Complete April 15, 2006Kugler Bench At SLAC May 15, 2006Kugler Bench Handover To SLAC June 15, 20061st Article Arrives At SLAC July 2, 2006MMF Ready For Measurements July 28, 2006Production Measurements Start August 29, 2006
(Approximate)
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
Undulator Measurement Benches
Ste e l Be lt
C a rria g e
Ha ll Pro b eX Y Sta g e
Ro ll Sta g e ,G o nio m e te r
G ra nite Ta b le
Line a r M o to r
C a rria g e
Ha ll Pro b eX Y Sta g e
Ro ll Sta g e ,G o nio m e te r
G ra nite Ta b le
ANL Bench DESY Bench
LCLS-TN-03-7
Goal: Move probes along a very straight line through the undulator.
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
Kugler Bench
On order, expected at SLAC May 15, 2006. Ready for use June 15, 2006.
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
SLAC Software Development Bench
Bench software by Seva Kaplounenko
(While we waiton the Kuglerbench)
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
Undulator Measurement Steps1) Place undulator2) Mechanically align undulator to bench3) Magnetically align Hall probe to undulator4) Perform any required large gap adjustments and re-align5) Straighten the X and Y trajectories6) Minimize phase errors7) Perform phase matching8) Determine K vs X, move probe to the X value which gives
the specified K9) Add fiducialization magnets to undulator ends, locate
center of fiducialization magnets10) Move undulator to CMM, finish fiducialization
LCLS-TN-03-7
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
1) Place Undulator
Ben Poling placing the ANL prototype on the SLAC prototype bench 12/9/05.
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
1) Place Undulator
Built by Gordon Bowden, Yurii Levashov, Scott Jansson
SLAC CAM Movers
Brake
Motor
HarmonicDrive
Cam PotentiometerBearing
Bearing
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
2) Mechanically Align to BenchUse Capacitive Sensors
We tested capacitive sensors in TTF undulators at DESY
Yurii Levashov
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
2) Mechanically Align To Bench
Undulator aligned to fixed height of reference pole.
Zack Wolf
Undulator Magnetic Measurements [email protected]
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
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
3) Magnetically Align Hall Probe
By
y
By
x
By
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
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
3) Magnetically Align Hall Probe
SLAC Measurements
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
4) Perform Any Large Gap Adjustments
ANL TB-48
Tapered Shim
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
5) Straighten X And Y Trajectories
LCLS-TN-05-5
Simultaneously measureBx and By (Hall)
and Bx from a coil
Zack Wolf
Undulator Magnetic Measurements [email protected]
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
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
5) Straighten X And Y Trajectories
MeasuredX
Trajectory
CalculateShims
ModeledX TrajWithCalc
Shims
MeasuredX Traj
After CalcShimsApplied
Automate Shimming, Under Development
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
5) Check Hall Probe Field Integrals
150 Turns
I1 I2
Long CoilLCLS-TN-05-22
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
5) Earth’s FieldLCLS-TN-05-4
We will eithera) Measure the field integrals and shim in the tunnelb) Put a mu-metal shield around the undulators (Isaac Vasserman)
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
6) Minimize Phase ErrorsPoles 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
MeasuredPhaseErrors
CalculatedShims
Under development
Zack Wolf
Undulator Magnetic Measurements [email protected]
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
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
7) Phase Matching
Phase Matching Shim Data
Entrance:Number of end poles = 5Measured 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 degEntrance phase error (from pole 6) = -12.03 degEntrance phase match shim dimension = 0.0000e+000 m
Program provides shim information
(under development)
pi pi/2pi/2 (mod 2pi)
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
8) Determine K vs XSinusoidal Field
K XK0
Canted Poles
K vs X
LCLS-TN-04-7
Set the probe position to give the nominal K value.
K Shim DataMeasured K value = 3.627747Desired K value = 3.500000Required field change dB / B = -3.6499e-002Required gap change dgap = 2.1330e-004 mBeam x motion required dx = 4.7401e-002 m
Analysis Program Gives K For Each X RunCalculated Undulator Parameters:Keff = 3.627747Beff = 1.295076 TLambda_rad = 1.595811e-010 m
X0(prototype)
(under development)
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
9) Add Fiducialization MagnetsNeed to relate magnetic field to tooling balls.
Attach to undulator ends, measure offsets
LCLS-TN-05-10
Yurii Levashov
Zack Wolf
Undulator Magnetic Measurements [email protected]
April 11, 2006
10) Move to CMM, Finish Fiducialization
Want DD1 : Magnetic MeasurementD2 : CalibrationD3 : CMM
D = D1 + D2 + D3
Zack Wolf
Undulator Magnetic Measurements [email protected]
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.