Dee Voltage Calibration of 31.02 MHz Cyclotron Resonance Cavity

The 31.02 MHz cyclotron RF system of Heavy Ion Medical Machine(HIMM) in IMP(Institute of Modern Physics, Chinese Academy of Sciences) has completed the design and commssioning,and now has already been put into operation. Its peak voltage requires 70 k V, but the precise calculation of the Dee voltage is still a difficulty problem, we can get the value Rp/Q0 of the cavity by CST simulation, and then combining the actual input power for cavity to calculate the real Dee voltage. In order to verify its accuracy, we use the bremsstrahlung method to test the cavity voltage under the condition of same input power. The error between test results and calculation is less than 0.6%.