An H−/light ion synchrotron for radiation therapy

An H−/light ion synchrotron to be used for radiation therapy of cancer is described. The synchrotron is designed to accelerate both protons and H− ions to a final energy in the range 60–250 MeV; with H− ions extraction is achieved by charge exchange of the circulating beam in a thin foil. The accelerator can be upgraded to accelerate fully stripped light ions (up to 16O8+) to 120–400 MeV/u with the addition of a second injector. The paper describes the lattice, the RF capture and acceleration schemes, the extraction systems with particular reference to the charge exchange method and the necessary upgrading to light ion acceleration.