Magnet structure for an isochronous superconducting compact cyclotron

摘要

The invention relates to a magnet structure for a superconducting isochronous cyclotron for use in particle therapy. The cyclotron according to the invention is using two sets of three or more superconducting sector coil elements for generating an azimuthally varying magnetic field across the acceleration region. In this way, high-field (e.g. above 4 T) isochronous cyclotrons are provided which do not suffer the problem of a low flutter amplitude.

主权项

1. A magnet structure for an isochronous compact cyclotron for generating a magnetic field across an acceleration region and whereby said magnetic field is perpendicular to a median plane of said acceleration region, said magnet structure comprising:
a superconducting coil assembly, a ferro-magnetic assembly for guiding a magnetic flux, and a cavity forming said acceleration region, wherein said superconducting coil assembly comprises a series of three or more superconducting sector coil elements located on top and below said acceleration region, each sector coil element having legs for leading a current in different directions, said sector coil elements being configured for varying azimuthally said magnetic field between a lower magnetic field value and a higher magnetic field value, and said ferro-magnetic assembly comprises magnetically interconnected portions for guiding a magnetic flux from each of said sector coil elements.