TIME-RESOLVED VOLTAGE BREAKDOWN IN VARIOUS INSULATORS DUE TO 2-MeV ELECTRONS

摘要

A pulsed beam of electrons from a 2-MeV Febetron was injected into several insulating materials and the resultant self-breakdown characteristics of the materials were studied. The materials included lucite, vinyl chloride, polyeth¬ylene, Teflon, pyrex, type 815 epoxy, and pyrex glass. The threshold for for¬mation of Lichtenberg figures was estab-lished for several of the materials. High-¬speed photography was used to observe the figures as they formed in some of the transparent materials, and propaga¬tion velocities were established for some exposure levels. Propagation ve¬locities were found to vary as a function of exposure level for those materials and exposure levels in which we were able to obtain a measurement. Intensity of the main stems of the figures was increased in small pellets of some materials by exposing them in a liquid dielectric bath;that is, electrons deposited in the liquid apparently discharged through the main stems of the pattern in the solid dielec¬tric to a grounded point on the back cen¬ter of the solid material.