Current Status of Sumitomo’s Superconducting Cyclotron Development for Proton Therapy

Sumitomo Heavy Industries, Ltd. is developing a com-pact superconducting isochronous 230 MeV cyclotron for proton therapy. It is designed to produce 1000 nA proton beams for high dose rate cancer treatment. The cyclotron magnet, which includes a liquid-helium-free cryostat, has been fabricated and the magnetic field has been measured. Magnetic field distribution and pa-rameters such as horizontal and vertical tunes agreed well with the original design. A 120 kW solid-state RF system is being tested. Other components such as the ion source and electrostatic deflector are being fabricated. After the testing of individual components, they will be assembled and beam testing will be scheduled at a new test site.