Magnets

Magnet Measurements

Paper Title Page
MPPT020 Magnetic Field Measurement on a Refined Kicker 1682
 
  • T.-C. Fan, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  
  To prepare for the operation of top-up mode and increase the efficiency of injection at storage ring, National Synchrotron Radiation Research Center (NSRRC) has upgraded the kicker magnets and power supply. We have built up a new magnetic field measurement system to test the kicker. This system, including a search coil and a coil loop, can map the field and take the first integral of field automatically. We also simulate the trajectory of electron beam by pulsed wire method of field measurement. We analyze the performance of the kicker system in this paper.  
MPPT021 Magnetic Measurement System for the NSLS Superconducting Undulator Vertical Test Facility 1730
 
  • D.A. Harder, G. Rakowsky, J. Skaritka
    BNL, Upton, Long Island, New York
  
  One of the challenges of small-gap superconducting undulators is measurement of magnetic fields within the cold bore to characterize the device performance and to determine magnetic field errors for correction or shimming, as is done for room-temperature undulators. Both detailed field maps and integrated field measurements are required. This paper describes a 6-element, cryogenic Hall probe field mapper for the NSLS Superconducting Undulator Vertical Test Facility (VTF). The probe is designed to work in an aperture only 3 mm high. A pulsed-wire insert is also being developed, for visualization of the trajectory, for locating steering errors and for determining integrated multi-pole errors. The pulsed-wire insert will be interchangeable with the Hall probe mapper. The VTF and the magnetic measurement systems can accommodate undulators up to 0.4 m in length.

*J. Skaritka et al., MEDSI’04.

 
MPPT023 A New Magnetic Field Integral Measurement System 1808
 
  • J.Z. Xu, I. Vasserman
    ANL, Argonne, Illinois
  
  Funding: Work supported by U.S. Department of Energy Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

In order to characterize the insertion devices at the Advanced Photon Source (APS) more efficiently, a new stretched-coil magnetic field integral measurement system has been developed. The system uses the latest state-of-the-art field programmable gate array (FPGA) technology to compensate the speed variations of the coil motions. Initial results demonstrate that the system achieves the system measurement accuracy of 0.15 Gauss centimeter (G-cm) in a field integral measurement of 600 G-cm, probably the world’s best accuracy of its kind.

 
MPPT024 Rotating Coil Magnetic Measurement System and Measurement Results of Quadrupole Prototype for BEPCII Storage Ring 1844
 
  • L. Li, W. Chen, G. Ni, X.J. Sun
    IHEP Beijing, Beijing
  
  A normal quadrupole prototype magnet with 266-mm long, 105-mm aperture has been designed and fabricated by IHEP. Total of 88 quadrupole magnets are under fabrication. The multipole components, magnetic field gradient and transfer function of the quadrupole magnets were measured in September 2004, using an updated measurement system, which includes a rotating coil measurement system and a Hall probe measurement system. This paper mainly describes the updated harmonic coil magnetic field measurement system and provides the measurement results for BEPC II quadrupole magnets.  
MPPT028 An Air Bearing Rotating Coil Magnetic Measurement System 2038
 
  • S.C. Gottschalk, K.W. Kangas, D.J. Taylor, W.J. Thayer
    STI, Washington
  
  This paper describes a rotating coil magnetic measurement system supported on air bearings. The design is optimized for measurements of 0.1micron magnetic centerline changes on long, small aperture quadrupoles. Graphite impregnated epoxy resin is used for the coil holder and coil winding forms. Coil holder diameter is 11 mm with a length between supports of 750mm. A pair of coils is used to permit quadrupole bucking during centerline measurements. Coil length is 616mm, inner radius 1.82mm, outer radius 4.74mm. The key features of the mechanical system are simplicity; air bearings for accurate, repeatable measurements without needing warm up time and a vibration isolated stand that uses a steel-topped Newport optical table with air suspension. Coil rotation is achieved by a low noise servo motor controlled by a standalone Ethernet servo board running custom servo software. Coil calibration procedures that correct wire placement errors, tests for mechanical resonances, and other system checks will also be discussed.