Magnetic field measurements in quadrupole magnets
Date
1973
Authors
Fyvie, Robert David
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Abstract
Magnetic field measurements have been made on a 4" diameter aperture beam-line quadrupole magnet. One method of measurement uses a rotating coil with a narrow bandwidth wave analyzer and the other a Hall plate survey system interfaced to an on-line mini-computer. The measurements are analyzed to yield the pole tip field as a function of the excitation current, the harmonic content of the field both as a function of axial position and of the entire magnet and the effective length of the field.
Quadrupole field measurements using a short rotating coil are analyzed to determine the fringe field configuration. Errors in the two methods are considered in detail, including the effect of misalignment of the rotating coil and cross-coupling in the Hall plate.