Radiation Induced Conductivity in Polyethylene and Teflon

Abstract

The conductivity induced in polyethylene and Teflon by bombardment with x‐rays from a 2‐Mev Van de Graaff and gamma rays from Co⁶⁰ has been investigated as a function of time, temperature, geometry, exposure rate, and applied electric field. Within the range of the variables studied, the observed photocurrents were directly proportional to the exposure rate and the applied electric field. The photocurrent could be divided into three components, the current due to the action of monodirectional photons, the increase in this current due to the influence of the electric field, and a component of less than 10% made up of all other possible charge carriers. During irradiation, the conductivity increased by a factor of about 10³. Between 78°K and 273°K the photocurrent was nearly independent of temperature. In general, the conductivity of Teflon was greater than that of polyethylene.