Reflectivity (rocking) curves of imperfect crystals by an improved Δω, Δ2Θ technique

A simple experimental modification to the Δω, Δ2θ technique for measuring single-crystal Bragg reflections has been demonstrated [Mathieson & Stevenson (1984). Aust. J. Phys. 37, 657-665]. This leads to a significant improvement in this technique in that the source component is reduced to a minor (angular) role, so that the greater resolution-capability/information-content, inherent in the Δω, Δ2θ method relative to the conventional Δω profile method, is further enhanced. With only two major components in the two-dimensional distribution, the individual distributions of these components can be determined with some accuracy. These components are the reflectivity (often referred to previously as the mosaic spread) and the wavelength distribution. The resolution function, R(Δω, Δ2θ), can be estimated from the experimental parameters and is sufficiently small that the deconvoluted reflectivity for imperfect crystals is derivable. This procedure is demonstrated, in the present case, for a small single crystal of CuInSe₂.