X-RAY-DIFFRACTION STRUCTURAL INVESTIGATIONS OF A BICRYSTALLINE SYSTEMBY SECTION TOPOGRAPHY UNDER CONDITIONS OF ANOMALOUS BORRMANN ABSORPTION

The problem of spherical X-ray diffraction by a bicrystalline system w ith a thin surface layer is theoretically considered for a Laue set-up in the case mu t much greater than 1 under the condition of the exist ence of a crystal-lattice mismatch. The intensity distribution, contra st and period of the interference pattern are calculated. A method to determine the thickness and the lattice mismatch of the epitaxial or d istorted surface layer of a bicrystal is suggested.