Crystal Orientation and Lattice Parameters from Kossel Lines

Abstract

A Kossel x-ray diffraction pattern of a single crystal contains information concerning crystal orientation, structure, and lattice parameters. Procedures have been developed for determining orientations to within ±0.5°, identifying conics and calculating d spacings to within ±0.5%, and determining lattice parameters in any crystal system with errors as small as 10 ppm. Orientation and structure calculations can be made starting with position measurements taken directly from a Kossel pattern. Precision parameter determinations require that suitable intersections of conics appear in the Kossel pattern. This can be assured by selection of appropriate conics and wavelengths and the aid of a stereographic projection of the pattern. Computer programs handle the bulk of the calculations.