Angle-sensitive X-ray topographs obtained with Kossel lines

A simple method and simple camera of small size for obtaining X-ray topographs with a microfocus X-ray source are described and initial results and their interpretation are given for an LiF crystal. The method is based on scanning a Kossel line across the recording film by simultaneously translating the crystal and film relative to the source and to a stationary mask that blocks most of the scattered and fluorescence radiation. The mask, which is located between the specimen and the film, is made by using the Kossel line recorded on a film in the mask plane as a pattern; this provides self-alignment of the system. Theoretical calculations are given that indicate the potential angular resolution of the method when applied to nearly perfect crystals. The advantages of this method over similar methods using the X-ray continuum diverging from a point source are discussed.