1. Magnetic Measurements At SLAC
Zack Wolf,
Scott Anderson, Ralph Colon, Brendan Dix, Scott Jansson, Dave Jensen, Luis Juarez, Seva Kaplounenko, Yurii Levashov, Wei Wang, Achim Weidemann

2. Magnetic Measurements Outlook
PEP II, ceases operation by 2009, magnetic measurements nearly complete
SPEAR III, running, magnetic measurements nearly complete
ILC, SLAC proposed warm design, not chosen, now what???, getting superconducting magnet to study center shifts during BBA
LCLS, SLAC’s next big project, many undulators to measure, many conventional magnets also

3. New Undulator Measurement Lab
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

4. LCLS Undulator (At ANL) Probe Air Undulator Bearing Belt Drive
Cam Mover
Bench

5. Purchasing Measurement Bench
(Similar to ANL bench
Shown)
X, Y Stage
Hall Probe
Carriage On
Air Bearings
Undulator
Granite Bench
Steel Belt
Linear Scale

6. Undulator Bench Construction Requirements
Parameter
Probe
Motion
Quad
Limit
Units
Carriage x deviation Dx 40 mm
Carriage y deviation Dy 14
Carriage roll deviation
mrad
Carriage pitch deviation
Dy, Dz
4.2
Carriage yaw deviation Dz

7. Initial Placement Of Undulator
Probes at nominal height
Cam movers move undulator to probes

8. Place Undulator (cont.)
Capacitive Sensors, Mechanical Alignment
Magnetic Alignment By y By x By

9. (very low offset drift)
Probe Construction
(and Hall probe)
Preamp
(very low offset drift)
Use SENIS Hall probe.
Hall Probe
(need 10-4 acc →
good calibration
System)
Coil
(6000 turns 1 mil wire,
4x6x12 mm, 0.2 m2)

10. Hall Probe Calibration System
Under construction
Flowing water NMR: 1 probe
Small chiller for probe temperature

11. Undulator Field Integrals
Long Coil
150 Turns I1 I2

12. Undulator Fiducialization Magnets
Need to relate magnetic field to tooling balls.
Attach to undulator ends, measure offsets
See Yurii Levashov’s talk

13. Temperature Measurements
Desired Measurement Accuracy 0.01 C

14. Quadrupole Fiducialization

15. Quadrupole Strength And Harmonics
Use Rotating Coil Systems
Examples Of Rotating Coil Systems

16. Conclusion Our 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.
The quadrupoles will be measured for strength and harmonics
with a rotating coil.
The quadrupoles will be fiducialized using the vibrating wire
technique.