Initiation of vacuum insulator surface high-voltage flashover with electrons produced by laser illumination

Abstract

In this paper, experiments are described in which cylindrical vacuum insulator samples and samples inclined at 45 relative to the cathode were stressed by microsecond timescale high-voltage pulses and illuminated by focused UV laser beam pulses. In these experiments, we were able to distinguish between flashover initiated by the laser producing only photo-electrons and when plasma is formed. It was shown that flashover is predominantly initiated near the cathode triple junction. Even dense plasma formed near the anode triple junction does not necessarily lead to vacuum surface flashover. The experimental results directly confirm our conjecture that insulator surface breakdown can be avoided by preventing its initiation [

A Repetitive Low Impedance High Power Microwave Driver

“…The vacuum interface of the high-power microwave diode is both a high-voltage feedthrough and a support structure for the cathode. The design of the vacuum interface is very important to its normal operation, and one of the keys is to suppress the occurrence of flashover along the surface [35]. A ceramic liquid-vacuum interface [36][37][38], as shown in Figure 11, is used to improve the vacuum level within the electron diode and the HPM tube.…”