PROPAGATION OF X-RAYS IN DISTORTED CRYSTALS UNDER DYNAMIC DIFFRACTION

The basic equations of the dynamical theory of X-ray diffraction for distorted crystals (the Takagi-Taupin equations) are derived and reviewed in two most useful forms. Numerical methods of their solution for a general deformation and for the case of depth-depending strain gradients are discussed. Applications of simulation techniques for studies of physical effects accompanying propagation of X-ray beams in distorted crystals (curved trajectories, interbranch scattering, Fraunhofer diffraction, spherical-wave interferences, standing waves) are reviewed.