Development of klystron perveance and gain monitor in J-PARC Linac

Hori, Toshihiko*; Shinozaki, Shinichi ; Sato, Yoshikatsu; Mizobata, Satoshi; Fukui, Yuji*; Futatsukawa, Kenta*

The triode klystrons with a modulating anode have been used for the J-PARC linac. Recently, we exchanged four klystrons due to the frequent discharge at a modulating anode in the klystron tube. In order to understand the discharge mechanism and to estimate the time to replace the klystron, we need to monitor the long term performance of the klystron such as the degradation of a cathode emission current and the RF gain of the klystron tube and so on. Therefore, we started to develop the klystron perveance and gain monitor module (NIM Standard one). In this paper, we will present the design concept of the monitor module, and the first performance test result using the module prototype.