Charge buildup during electron irradiation

In recent years, several methods for the analysis of charge buildup in dielectrics during irradiation with a nonpenetrating electron beam have been developed. The most elementary model assuming a single range of electrons has been proposed by Gross et al. [1) in 1974. Two years later, Matsuoka et al. [2) included range straggling of electrons using experimental electron deposition and depth-dose curves. In 1979 Berkley [3) used a Monte Carlo simulation for the irradiation parameters to solve the nonlinear transport equation. In the same year Tanaka et al. [4) measured the reduction of the electron range due to space charge accumulation. Recently Gross et al. [5) generalized the original box model introducing a time dependent conductivity. In the present paper the different theoretical approaches are outlined and compared with each other for three boundary conditions. Additionally a modified box model including time dependent range of electrons is suggested.