Fixed field phase shifters for a multipass recirculating superconducting proton linac

The multi-pass recirculating proton linac can significantly improve the usage efficiency of rf superconducting cavities by accelerating beam through same cavity multiple times. However, in order to achieve acceleration for different energy beams, longitudinal phase synchronous conditions among these beams have be satisfied. In this paper, we propose a fixed field shifter system based on two bending magnets with an optimized distribution meet conditions. Such provides both delay and transverse focusing beams. Self-consistent macroparticle simulations including space-charge effects show that emittances well preserved after