Monochromators for Synchrotron radiation based on SiGe gradient crystals

This work is devoted to the investigation of monochromatization of the divergent synchrotron beam at the radiation diffraction by single crystals of silicon-germanium solid solutions with the given gradient of the lattice parameter along the sample surface. It has been shown that such crystals provide a high spectral resolution and increasing luminosity at a given radiation wavelength. The concentration dependence of the lattice parameter of SiGe crystals for compositions from 1 to 12 at % of Ge has been refined. The real structure of crystals has been analyzed by methods of two-crystal spectrometer and section topography. The description of the dynamic problem on the Bragg symmetric diffraction of the divergent beam of the X-ray radiation is represented for the case when the scattering vector is perpendicular to the direction of the lattice parameter gradient of the crystal. (C) 2000 Elsevier Science B.V. All rights reserved.