The dielectric behaviour of polymers irradiated at 5 K

Abstract

A measurement system was developed to carry out frequency domain dielectric spectroscopy and TSDC (thermally stimulated discharge currents) automatically on multiple samples which can be irradiated in helium over a wide temperature range from 5 to 300 K. The system was used to study the dielectric behavior of polyimide and low-density polyethylene (LDPE) as a function of temperature and gamma radiation. Measurements of loss in polyimide and LDPE gamma-irradiated at 5 K to doses of 10/sup 5/ Gy show no effects of radiation. A TSDC signal was observed for polyimide irradiated to 10/sup 5/ Gy. The small currents evident at low temperatures are probably due to geminate carriers, and there is a beta peak around 170 K.<>