Vacuum Insulator Flashover of Ultra High Vacuum Compatible Insulators

High voltage vacuum systems with stringent vacuum requirements are often designed with ceramic insulators which have low flashover strength. In this paper, we report on experimental results comparing pulsed high voltage flashover of Rexolite®(cross-linked polystyrene), a pulsed power industry standard vacuum insulator, to Kel-F® (polyclorotrifluoroethylene), a plastic with significantly lower vacuum outgassing. Our results show similar surface flashover results with the two materials, with both exhibiting large spread in flashover electric field. The average electric field for flashover of each material agree well with predictions based on previously published results.