Filling of traps with electrons in insulators subjected to intense electron irradiation

The efficiency of nonequilibrium electron trapping by capture centers in alkali halide crystals, quartz, and polymethyl methacrylate exposed to an intense electron beam with a beam current density of about 20 A/cm² is studied. The trapped charge is estimated from the amount of irradiation-induced electrification of high-resistivity materials. It is shown that traps having captured thermalized electrons become depleted via impact ionization due to the primary electrons of the beam and secondary electrons.