Investigation of the long-term performance of the 324 MHz klystrons for achieving the efficient operation of the linac at J-PARC

J-PARCリニアックの効率的な運転を目指すための324MHzクライストロン長時間性能調査

堀 利彦; 篠崎 信一 ; 千代 悦司; 佐藤 文明; 川村 真人*; 二ツ川 健太*; 福井 佑治*; 小栗 英知  

Hori, Toshihiko; Shinozaki, Shinichi; Chishiro, Etsuji; Sato, Fumiaki; Kawamura, Masato*; Futatsukawa, Kenta*; Fukui, Yuji*; Oguri, Hidetomo

In order to achieve the efficient operation of RF power source, it is important to know the long-term performance of the klystrons under the operational conditions of the linac. Linac has been operated since November of 2006 for more than 35,000 hours. The performance of two klystrons taken away from on-line operation, serial number 0205 (S/N 0205) with operation history of 28,500 hours and S/N9901 with operation history of 32,000 hours were tested and were evaluated. Two klystrons were found to be still available at the klystron stations of the RF power lower than 1.2 MW and 1.0 MW, respectively. The long-term performance of these klystron were investigated at the RF test station. The results of the measurements showed that the main factor determining the life of the klystrons is the emission current of the klystron cathode as a thermionic electron source. From the results of the present work, the cathode lifetimes of the two klystrons can be evaluated to be more than 100,000 hours.