Short-Term Radiation-Induced Conductivity in Polystyrene Films with Narrow Molecular Weight Distributions

Thin disk dielectric film capacitors were prepared from a series of special monodisperse polystyrenes and irradiated in a flash X-ray facility. Transient conductivity in the films was measured with time resolution ≈ 5 ns, for dose rates from 107 to 5×1010; rad/sec, and related to a kinetic model dominated by carrier trapping. Estimates for constants associated with a class of shallow traps were obtained for the assumed model. No significant molecular weight dependence of the early-time induced conductivity was found. Molecular weight-dependent departures from second order decay kinetics were noted.