Calculation and measurement of Q factor for RF D-circuit of cyclotron

The paper introduces the calculation and measurement method of Q factor which describes the performance of cyclotron's RF D circuit. It mainly introduces the formula and principle for calculating the Q factor. The calculation data are compared with the measurement data of the capacitor coupling method, which shows good accordance with small errors. Analysis suggests that errors are mainly caused by approximate computation and the value of contacted resistance adopted. As contacted resistance is an important factor, more attention should be paid on it in designing cavities.