Present Status of High-Power Pulse-Modulator with a Thyratron

Abstract

This paper describes present status of klystron modulators for the KEK electron-positron injector linac. The rf system of this linac consists of 60 high-power klystrons, each capable of 50 MW, 4.0 µs pulsed power at a repetition rate of 50 pps. Each klystron is pulsed by its own line-type modulator, containing a hydrogen thyratron switch tube. The modulator availability and thyratron lifetimes are presented. A 45 kV solid-state switch consisting of 15 static-induction (SI) thyristors stacked in series has been also developed and tested to replace a thyratron, which improves the reliability and maintainability of the modulators.