Development of self-healing capacitors for klystron pulse modulators

Summary form only given. We developed a self-healing capacitor to realize a compact pulse-forming network for klystron pulse modulators. The structure of the capacitor element consists of polyethylene terephthalate and polypropylene films, and the former film is coated with thin Ze-electrodes which form series of capacitors. The capacitor has a capacitance rating of 45 nF and a voltage rating of 55 kV, and the dielectric stress was designed to be about 120 V/micrometer. The design life was 9 G shots. Compared to a conventional nonhealing capacitor, the energy density increased more than three times. The capacitors have been operating in the electron linear accelerator of accelerator test facility at KEK and have achieved about 1 G shots without any serious problem, This paper describes the design and test results of the lifetime performance.