Physical Review Special Topics. Accelerators and Beams (Sep 2004)

Design study of compact medical fixed-field alternating-gradient accelerators

  • T. Misu,
  • Y. Iwata,
  • A. Sugiura,
  • S. Hojo,
  • N. Miyahara,
  • M. Kanazawa,
  • T. Murakami,
  • S. Yamada

DOI
https://doi.org/10.1103/PhysRevSTAB.7.094701
Journal volume & issue
Vol. 7, no. 9
p. 094701

Abstract

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We have studied the various conditions and limitations for achieving compact fixed-field alternating-gradient (FFAG) accelerators to be widely used in heavy-ion cancer therapy. For the case of a normal-conducting FFAG accelerator, our linear calculation indicates 12-cell radial sectors with a field index of 10.5 as a suitable configuration. We found that its ring circumference can be as small as 70 m and that triple-cascade rings are needed to accelerate a carbon beam from 40 keV/u to 400 MeV/u. In this paper, we report a systematic analysis based on a linear optical model, a comparison of various types of FFAG, and a design example with some technical concerns. An important result is that viable radial-sector designs are possible with circumference factor C significantly lower than the value 4.45 previously quoted.