Power Supply for Magnet of Compact Proton and/or Heavy Ion Synchrotron for Radiotherapy

A resonant type pulse power supply, for an application to a compact proton and/or heavy ion synchrotron with a several Hz repetition rate, is attractive from the view point of attaining an average beam current that is enough for the radiation therapy. Maximum ampere-turn of the dipole magnets is as large as 200 kAT corresponding to dipole field of 3T to make the bending radius as small as possible. Pulse current is generated by discharging the stored energy of a capacitor bank through a pulse transformer. Moreover, the auxiliary power supply for the dipole magnets which adds the flat magnetic field (10-20μs) for the multi-turn beam-injection is being developed. The power supply for the quadrupole magnets is the high frequency (20 kHz × 5) switch-mode power supply which enables the fine tuning and the accurate tracking between the quadrupole and dipole fields. Detailed analysis on these pulse power supplies will be presented.