Generation of secondary electrons and radiation defects in matter during absorption of electrons with energy above 1 MeV

Abstract

Using the model of sections with one-dimensional geometry, the output of δ electrons generated by electrons with energies from 1 to 10 MeV is considered as a function of the thickness and the atomic number of various absorbers. The depth distributions of thermalized electrons and radiation defect profiles are calculated for the model absorbers KCl and NaCl. Radiation defects due to irreversible displacement of lattice atoms upon elastic scattering of rapid electrons are considered. The microphotometry method is used to obtain depth distributions of enrichment centers in the ionic crystals KCl and NaCl for irradiation by electrons with energies E=1, 1.5, and 2 MeV for electron-beam incidence on the absorbers at angles ofΘ0=0, 20, 45°. The integral density of the incident beam was varied from 1·1014 to 6·1015 cm−2. It was found that in ionic crystals the enrichment center density is proportional to the density of thermalized δ electrons, if the concentration of radiation defects generated is less than 1% of the density of preradiation anion vacancies.