ANL, Argonne, USA
PAC, Batavia, Illinois, USA
Like the cyclotron, the Fixed Field Alternating Gradient machine (FFAG) is a compact accelerator with variety of applications in industry and medicine. High intensity, fixed-field compact accelerators require enhanced orbit separation to minimize beam losses especially at extraction. In medium energy and compact FFAGs, this requires a total voltage of ~20 MV per turn with continuous wave accelerating gradients of ~10MV/m, which can only be achieved using superconducting accelerating cavities. This high voltage can be generated using 4 superconducting (SC) cavities operating at higher harmonics of the beam revolution, equal to approximately 200 MHz. The cavities and cryomodule are inserted into a 2m straight section of a racetrack-shaped FFAG. However, as with cyclotrons, the FFAG has a large horizontal acceleration aperture presenting a challenging problem for SCRF cavity design. In this work, we present SC cavity design with 50 cm x 1 cm beam apertures, their electrodynamics optimization, and multiphysics analysis. To achieve a 1 mA average beam current, each cavity is powered by two 100 kW RF couplers.
