Theoretical and experimental principles of the differential-integral triple-crystal X-ray diffractometry of imperfect single crystals

The proposed new method of the differential-integral triple-crystal X-ray diffractometry of imperfect single crystals is justified theoretically and experimentally. The principles of the work of triple-crystal diffractometer (TCD) in the differential mode of measurements are described. Original construction and scheme of the universal TCD created in IMPh, N.A.S. of the Ukraine with the aim of realization of the proposed method are shown. In the Bragg case of X-ray diffraction by single crystals containing homogeneously distributed bounded defects, the relationships are obtained that establish the analytical relation between the ratio of the integrated intensities of diffuse and coherent TCD peaks from the investigated crystal, namely, the ratio of the differential diffuse and coherent scattering intensities both integrated over the Ewald sphere near the reciprocal lattice point and the characteristics of various kind defects. The obtained relationships are applied to the highly informative characterization of defects by using the angular dependences of the integral parameters of TCD intensity profiles measured from the silicon single crystal, which contains chaotically distributed new phase particles. The advantages of the proposed modification of TCD method are discussed.