MEASURING MULTIPOLE FIELD ERRORS IN MAGNET APERTURES OF LARGE ASPECT RATIO BY MEANS OF AN OSCILLATING WIRE ON ELLIPTIC TRAJECTORIES

• Abstract:

  Errors in the transversal field of accelerator magnets are usually expressed in terms of the coefficients of a harmonic expansion on a circular trajectory in the magnet’s aperture.
  An elliptic trajectory more suited to apertures with large width-to-height ratios allows the field inside the domain to be reconstructed with a higher accuracy. Displacing an oscillating wire along an elliptical trajectory and acquiring the amplitude of the wire oscillation at each point yield a periodic signal to be expanded into the elliptic multipoles. The paper discusses the theoretical background, the practical implementation in the measurement system, and the accuracy achieved in the measurements of a quadrupole magnet.
• Keywords:

  magnetic measurements, accelerator magnet, multipole field expansions
• Download:

  IMEKO-WC-2012-TC4-O13.pdf
• DOI:

  _unreg_wc-2012.TC4-O13

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