RF cavities and power amplifier for the compact proton synchrotron

A project to build a compact proton synchrotron is now underway. Protons will be accelerated from 2 MeV to 200 MeV within 5 ms with an operation repetition rate of 10 Hz, in the synchrotron ring with a circumference of 11.9 m. The acceleration system is required to be of a wide bandwidth, with the frequency sweeping from 1.64 MHz to 14.26 MHz, and of a high gradient, with the maximum acceleration voltage of 20 kV. The acceleration section, consisting of a 2-cell rf cavity loaded with 4 high-permeability magnetic alloy cores in each cell, has been designed. A push-pull power amplifier with two 35 kW tetrode tubes will be used to drive the 2 cavities in parallel. Calculations and test results on the cavity characteristics will be presented and discussed, including the cavity impedance and equivalent circuit. The simulation results of the amplifier system using the ICAP code will also be given. The prototype of the rf system is being developed, and a high power test will be performed soon.