Performance of a high-power klystron using a BI cathode in the KEK electron linac

Fifty-megawatt high-power klystrons in the KEK electron linac have used a larger diameter cathode of 85 mm. Stable operation requires a careful manufacturing process of the cathode and a low-gradient gun design. Therefore, the klystron manufacturing, including a cathode processing, has been improved so as to obtain stable performance. This paper presents the klystron improvements associated with using the BI cathode and klystron operation statistics for the past 17 years. q1999 Elsevier Science B.V. All rights reserved.