THEORETICAL-ANALYSIS OF TRANSIENT RADIATION-INDUCED CONDUCTIVITY OF POLYMERS WITHIN THE ROSE-FOWLER-VAISBERG MODEL

The transient behavior of radiation-induced conductivity both during i rradiation and at the relaxation stage after cessation of irradiation is studied. An analytical expression describing the decay of radiation -induced electric conductivity is derived within the Rose-Fowler-Vaisb erg (RFV) model at low intensities of the radiation pulses is suggeste d and compared with direct numerical computations. Convenient experime ntal techniques for determining the basic parameters of the RFV model (effective frequency factor, displacement of thermalized charge carrie rs prior to their capture in unit electric field, and dispersive param eter) are proposed based on the calculation results. The suggested met hod for determining parameters of the RFV model is checked using as an example the available literary data for polystyrene and low-density p olyethylene. Along with an analysis of the low-signal mode, we scrutin ized also nonlinear effects associated with bimolecular recombination of charge carriers and filling the traps. The temperature dependence o f the radiation-induced conductivity and its relation to molecular mob ility in polymers were tentatively studied.