Design study of a rotating gantry for the HIMAC new treatment facility

A project to construct a new treatment facility as an extension of the existing HIMAC facility has been initiated for the further development of carbon-ion therapy. In the new facility, one of the treatment rooms will be equipped with an iso-centric gantry system employing a 3D pencil beam scanning irradiation method. In order to realize a compact design, the final 90° bending magnet is divided into two bending magnets of 60° and 30°. The scanning magnets are set between these two bending magnets, although the aperture of the 30° magnet increases. Finally, we achieved 350 tons of total weight for 400 MeV/u carbon beams with a 150 mm square field.