The effect of bending of reflecting planes of the crystal lattice on the formation of a diffraction image in section topography was studied by numerical integration of the Takagi equations. All calculations were performed for the case of small absorption and a real experiment. The intensity of the reflected wave exhibited a dependence on the sign of bending (violation of Friedel’s law). The integrated intensity of the diffracted wave increased linearly at large divergence of the incident beam (much larger than the angular region of reflection of an ideal crystal). In contrast, at a small divergence, it tended to saturation rather than increasing linearly. The decrease in the integrated intensity was associated with the part of the wave field propagating along the edge of the scattering triangle.
Smirnova et al. (Mon,) studied this question.