Heavy Ion Injection of Fixed-Field Alternating Gr adient Acceler ator

Much r esear ch in r ecent years has focused on cir cular accelera tors tha t accelera te and store secondary particles with a large momentum spread, such as muons, unstable nuclei, and heavy ions with different charge states. A fixed-field alternating gradient (FFAG) accel- erator with large transverse and momentum acceptance has ob vious advanta ges for such r equir ements. A versatile beam injection method is r equir ed to accelerate secondary parti- cles with a large momentum spread and different charge states with an FFAG accelerator. In the present study, a method for charge exchange injection of positi v e heavy ions using the large momentum acceptance of an FFAG accelerator is proposed. A charge injection system, which converts a He 1 + beam to a He 2 + beam, is de v eloped for a 150 MeV FFAG accelera tor a t the Center for Accelerator and Beam Applied Science (CABAS) of Kyushu Uni v ersity. As the first step to verify the injection method, an orbit shift from one charge state to the other is demonstrated. This is the first demonstration of heavy ion injection using an FFAG accelerator.