부산대학교 도서관

Statistical characterization of vacuum surface flashover is achieved by electrically stressing a positive 45° wedge of cross-linked polystyrene (Rexolite) with a fast, high-voltage pulse. The insulator is placed between a hemispherical anode with a 2 cm radius extending into a parallel plate planar cathode. This configuration is intended to confine the flashover plasma to a ~1 cm wide region on the surface of the insulator for repeatable optical access. The voltage source comprises an 8-stage Marx generator that can provide a pulse up to 264 kV with a ~50 ns risetime. Two capacitive voltage dividers are used as voltage diagnostics for the system. They are placed on the high-voltage coaxial cable entering the vacuum chamber and on the ground side of the flashover gap. A current viewing resistor (CVR) is placed into the outer shield of the high-voltage coaxial cable as the current diagnostic. A DSLR camera is employed to capture a time-integrated image of the flashover event. Pulse voltage, current, and risetime statistics are collected and reported for a statistically significant sample size for a 2.5 mm gap.