Study of a Linac Booster for Proton Therapy in the 30-62 MeV Energy Range

Recent results in accelerator physics have shown the feasibility of a coupling scheme between a cyclotron and a linac for proton acceleration: a 60MeV proton beam has been successfully captured and accelerated by a prototype module (LIBO) of a 3GHz linac. While the number of 60MeV cyclotrons is limited, a large number of 30MeV ones, mainly devoted to radioisotopes production, is available in medical centres. These two evidences have suggested the idea to study and design a 30MeV linac post-accelerator able to bridge the gap between the 30MeV commercial cyclotrons and the 60MeV LIBO. The main challenge in such a research project is related to meet the requirements arising from the beam dynamics with the constrains due to the mechanical structures and tolerances and to the heat dissipation mechanism chosen in the design. In this paper we will review the rationale of the research project and we will discuss the basic design of a compact 3GHz linac with a new approach to the cavities used in a SCL (Side Coupled Linac) structure.