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

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

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

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

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

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

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

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

(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)

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

Undulator Field Integrals Long Coil 150 Turns I1 I2

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

Temperature Measurements Desired Measurement Accuracy 0.01 C

Quadrupole Fiducialization

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

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.