大電流CW電子線形加速器の要素開発(IV) -加速管クライストロン窓大電力RF試験速報-

The key development of high power CW electron linac(IV); Preliminary result of high power experiment for a traveling wave resonant ring and klystron output windows

遠山 伸一  ; 江本 隆; 平野 耕一郎  ; 尾下 博教 ; 野村 昌弘  ; 武井 早憲   ; 高橋 伸友

Toyama, Shinichi; not registered; Hirano, Koichiro; Oshita, Hironori; Nomura, Masahiro; not registered; Takahashi, Nobutomo

標記加速器の開発のための主要機器の加速管、クライストロンなどの設計研究及び試作を行い、これら試作機器の大電力RFでの性能評価試験を行った。すでに試作したクライストロンを大電力RF源として、クライストロン、加速管及びクライストロン用RF出力窓の試験体系を構築し、評価試験を行った。1)加速管では、目標の800kWまでのRF電力を安定に印加することができ、ビーム無負荷での目的をほぼ達成した、2)クライストロン出力窓では、目標以上の最大1.7MW、Lバンドでは世界最大級の大電力に耐える窓の開発に成功した、などを報告した。

[Background] Development of a CW electron linac which can accelerate a few order higher beam current is under development in PNC. So far, design of main components: accelerating tube and a klystron has been carried out. This time high power RF experiment of the developed components was carried out without electron beam. [Objective] An experiment with high power RF was carrying out in order to validate the design of the components. In regard to ceramic windows for the klystron, improvement of its design was found necessary in accordance with the experiment in last year. Therefore the design was improved, and high power RF experiment was carried out for test window manufactured based on the improved design. [Method] The test system for a accelerating tube and klystron windows was constructed and high power RF experiment was carried out using this system where the trial klystron was used as high power RF source. The experiment was carried out in National Laboratory for High Energy Physics (KEK) in Tsukuba where the high voltage DC power supply is available. [Result] The traveling wave resonant ring was successfully driven with 800 kW RF power which is around the final goal in the case of no beam loading. The unexpected thermal dissipation was observed at the phase shifter of the resonant ring because of its high RF attenuation. The klystron windows that have the optimized design dimension could transmit the 1.7 MW RF power which is strongest over the world in L-band. [Conclusion] The validity of the design of traveling wave resonant ring and klystron windows was demonstrated by high power RF loading experiment. But, the phase shifter needs more improvement to make it possible to use under hundreds of high power RF.