X‐Ray Dynamical Contrast of a Planar Defect

Abstract

Abstract The presence of a non‐diffracting lamella in an otherwise perfect crystal results in particular interference fringes on X‐ray topographs. The form and contrast of these fringes as found on section topographs have been calculated using the basic assumptions of the dynamical theory. Two different types of fringes can be distinguished: those independent of the gap thickness which are similar to stacking fault fringes, and those characteristic of a gap, whose shape depends sharply on the gap thickness. It is shown that among these interference systems some fringes of high contrast exist even in absorbing crystals. The experimental results obtained with various geometric arrangements are in good agreement with the theoretical predictions.