X-ray standing waves on the surface of the crystal with the uniform strain gradient

Abstract
The results of theoretical investigation of X-ray Standing Waves (XSW) on the surface of the crystal with the Uniform Strain Gradient (USG) are presented. Bent crystals are the typical examples of the crystals with the USG. The proposed theory is based on the Takagi-Taupin theory of X-ray propagation in a weakly deformed crystal. This theory is applied for calculation of the angular dependencies of reflection coefficient and XSW on the surface of the crystal with USG for the specific case of Si(400) thick crystal, CuKa radiation. The behaviour of the XSW with the different position of adsorbed atoms (different values of the phase shift) are analyzed.