Kononenko O. Dynamical Theory of X-Ray Laue Diffraction in Toroidally Bent Crystals with Microdefects

Dynamical diffraction effects. Creation of the dynamical theory of X-ray scattering in toroidally bent crystals with microdefects. Establishment of the rigorous quantitative relations between experimentally measured distributions of intensity scattering in reciprocal lattice space at the Laue diffraction geometry and the defect characteristics and strain parameters. Research methods are perturbation theory, methods of statistical physics, dynamical diffraction theory, method of stationary phase, numerical methods. The dynamical theory of X-ray scattering in a crystal at the Laue diffraction geometry has been developed for the case of a toroidal bending at the presence of the fluctuation field of static displacements of atoms from randomly distributed microdefects. The concept of active excitation points on the dispersion surface has been introduced. This concept explains scattering mechanism in such crystals. It has been shown that the oscillating part of reflection coefficient is appreciably modifiedin dependence of values and signs of meridional and suggittal bending radii by shift and changing heights and widths of central and subsidiary peaks. Focusing effect and its dependence of defect parameters have been predicted. The obtained theoretical results coincide with the experiment. The influence of the bend on patterns of diffuse scattering intensity distribution has been shown to be more appreciable for defects with larger radii.