High-Power RF Testing of 1-MW, 352.2-MHz Continuous Wave Klystron Amplifier

Abstract

A 1-MW, 352.2-MHz continuous wave (CW) radio frequency (RF) test stand based on TH 2089 klystron amplifier is developed and tested up to its rated power. Klystron amplifier demands stringent performances from its beam bias power supply for its proper operation. A novel crowbar less solid-state modular topology is adopted for -100-kV, 25-A dc beam bias power supply and its achieved performance parameters are presented in this paper. Wire burn test, which is crucial for CW klystron amplifier, was conducted on this power supply to ensure that its stored energy during klystron arcing is less than 20-J. The criterion for the selection of test wire is also presented. A real-time control system is developed for proper sequence of operation of various power supplies as well as for control and monitoring of crucial parameters of this test stand. The testing of this high-power klystron amplifier is quite involved in nature and various tests have been carried out under several operating conditions before it is employed in the high-power RF test stand. This paper studies and analyzes the effect of variations of various parameters on the performance of this high-power klystron amplifier. Variation of output power and RF gain against RF input power as well as variation of RF phase over beam voltage is presented. Variations of RF output power against frequency, beam voltage, beam current, and mod-anode voltage are also presented. Heat run test was conducted on this klystron amplifier for 24 h to ensure its reliability.