Capacitor transient effects in a high-dose-rate environment

Abstract

At the National Ignition Facility, new designs for x-ray diagnostics and ICF targets place high energy density capacitors in the harsh radiation environment of the target chamber. In these applications, dielectric breakdown would be catastrophic. This study considers the behavior of three dielectric types in a prompt-dose radiation environment; aluminum electrolytic, multilayer ceramic, and metalized polypropylene. The experiments exposed the capacitors with a flash x-ray machine and measured the internal discharge from shot-to-shot for a range of doses. From the results, the thinner aluminum electrolytic dielectrics internally discharged less than the thicker ones. The results from the flash x-ray source were compared to a limited set of data taken in NIF’s neutron test-well. The aluminum electrolytic and metalized polypropylene capacitors did not fail while biased at their rated voltage during eight shots in NIF, mostly between 1e9 n/cm 2 and 4e9 n/cm 2 .