GaToroid: A novel toroidal gantry for hadron therapy

We describe here a novel concept of a gantry for hadron therapy, based on the use of a toroidal field configuration. The main features of this concept are that the gantry is not rotating, and is operated in steady-state We propose that is built based on superconducting magnets, reaching field levels not achievable using normal conducing iron-dominated magnets. The simplification resulting from the specific magnetic configuration, and the scale reduction that can be achieved using high-field superconducting magnets, bear a definite potential for significant reduction of dimensions and mass. In this paper we introduce the concept of the toroidal gantry, discussing the features of beam transport in a toroidal field. We then provide general considerations on the design of the coil, and analytical scaling of relevant indicators such as forces and stored energy. Finally, we give an example of practical layouts for a proton gantry that can be used as a benchmark for comparison with other designs.