Development of a superconducting magnet for synchrotron of heavy-ion radiotherapy system

Heavy-ion radiotherapy has a high curative effect and low burden on patients, so it has been spreading in recent years. However, since heavy-ion radiotherapy system have large apparatuses, it is necessary to downsize this apparatuses in order to further wide spreading. Therefore we considered applying superconducting technology to the synchrotron. In this study, we designed the superconducting magnet for the synchrotron. This magnet has saddle-shaped coils curved along the beam trajectory, and the cross section of these coils has elliptical shape in order to increase the magnetic field. AC losses of the superconducting coil were calculated because the magnets of synchrotron are operated fast. In this paper, we will report a recent status of the design study of this superconducting magnet. (author)