RF capture studies for injection into a synchrotron

The capture process for a rapid cycling proton synchrotron is studied by numerical simulation. The RF programming is optimized to allow efficient capture such that minimum particle losses and reasonable capture voltage are attained. The total capture time is constrained to be less than 700 μseconds. Two methods of trapping the injected beam by the synchrotron RF system are examined: by stationary adiabatic capture and by synchronous injection in a standing bucket of the ring. In the adiabatic method, the nonlinear function of Lilliequist and Symon(1959) is employed. The simulation allows the “tracking back” of the original distribution of any set of particles, in particular of those not captured at a given time, which is useful in studying injection alternatives such as shaping the phase-space density prior to injection. The simulation results will be used to design a chopper system to facilitate loss-free injection