X-Ray Diffraction Profiles for Near 180° Scattering from Mosaic Crystals

Abstract

Reflectivity curves have been calculated for mosaic crystals in the case of normal-incidence Bragg diffraction with soft X-rays. The enormously broadened angular width of a reflection when the angle of incidence to the reflecting Bragg plane approaches 90° allows a single crystal with a mosaic spread as much as a few degrees to give a reflectivity profile very similar to that of a perfect crystal, when the incident photon energy is scanned. The insensitivity of the diffraction process to crystal mosaicity can be exploited in standing-wave experiments aimed at the determination of substrate-overlayer interface structures.