Multicavity proton cyclotron accelerator

Analysis is presented for a multicavity proton cyclotron accelerator in. which a 122 mA, 1 MeV proton beam is accelerated to 954 MeV using a cascade of eight cavities in an 8.1 T magnetic field, with effects of finite beam radius and velocity and energy spreads taken into account. The first cavity operates at 120 MHz, and successive cavities have resonance frequencies lower in increments of 8 MHz. For this example, average acceleration gradient exceeds 37.9 MV/m, average effective shunt impedance is 207 MΩ/m, but maximum surface field in the cavities does not exceed 7.2 MV/m. Such an accelerator might be suitable for driving a high-power neutron spallation source.