PERVEANCE MONITOR FOR MEASURING AN 80-MW KLYSTRON CHARACTERISTICS*

The high power klystron-modulator (K&M) system is a main pulse and microwave source for the PLS linac. The peak powers of the modulator and the klystron have 200 MW and 80 MW, respectively. The total heater run time of an oldest klystron system has been accumulated over 75,000-hours as of now. This klystron must operate efficiently and stably in the linear gain region within a band of frequencies. The micro-perveance will change as the tube ages. It is believed that a change in the perveance of the klystron may be a predictor of when a klystron is about to fail. Therefore, it is necessary to monitor the klystron operational status for stable beam operation. It can be achieved by measuring the klystron micro- perveance to diagnose characteristics of klystron. Up to now, the operator manually performs it. The prototype perveance monitor system has been designed by processing the sensing signal of a beam voltage and current of the klystron. In this paper, the design concept and experimental results for application will be presented.