Electron-Induced Atomic Displacements near Threshold in Thin Single-Crystal Foils

Abstract

The cross section for atomic displacement produced by energetic electron beams is obtained in an approximate manner under the following conditions: (a) The electron beam is centered about a major crystallographic direction coinciding with a minimum in the threshold energy surface. (b) The electron beam has angular dispersion due to finite collimation and/or multiple scattering. (c) Energy degradation of the electron beam is accounted for. The displacement cross section is found to be a sensitive function of the angular beam spread and the crystal parameter describing the threshold-energy surface valley. An average cross section is computed for a number of cases and compared with available experimental data for copper.