Electron Diffraction Experiments Upon Crystals of Galena

Abstract

Cleaved surfaces of galena crystals yield electron diffraction patterns made up of Kikuchi lines, and spots which are drawn out into streaks by refraction. After etching, the spot pattern predominates and the individual spots are sharp. The lines are then rather diffuse and ill-defined. Rocking curves upon various Bragg reflections from the surface plane prove that the imperfection of a certain crystal does not exceed about 15 minutes, and that the projections through which the electrons pass are relatively thick. Estimates of imperfection and thickness made from rocking curves are in approximate agreement with those obtained from widths of Kikuchi lines.