Analytic solution for radiation-induced charging and discharging of dielectrics

Irradiation of a solid dielectric by ionizing radiation generates a radiation-induced conductivity. It allows one to remove or neutralize an macroscopic space-charge distribution that might have existed in the dielectric prior to the onset of irradiation. If irradiation is performed with charged particles, in particular electrons, transient charging currents are observed. The differential equation describing these effects is linear if the macroscopic space-charge drift term is neglected. This paper gives an analytic solution of this equation based on the general theory of linear passive relaxation systems. General aspects of the current observed during irradiation with partially penetrating electrons are discussed for different conductivity-depth profiles.