The modulator stability system for the BEPCII klystron

The stability of the modulator high voltage output pulse is very important for a klystron. The voltage stability of the BEPCII modulator demanded is less than plusmn0.15%. To achieve this target, we use a thyristor voltage regulator having a feedback function to stabilize the DC high voltage of the modulator and a De-Qing circuit to stabilize the PFN charging voltage. This paper describes the modulator stability system and the stabilization measurement.