Eikonal approximation of dynamical diffraction equations for X-ray beams with a two-dimensional curvature of the wave front. II. Focusing of an X-ray beam by a crystal with non-plane entrance and exit surfaces. Symmetrical Laue case

On the basis of eikonal approximation developed in the first part of this work, diffraction of X-ray beam with a two-dimensional curvature of wave front and its focusing by a crystal with nonplane entrance and exit surfaces is studied in symmetrical Laue case. The expressions for eikonal and focusing distances inside and outside the crystal in the vacuum, are obtained. The size of the focal spot and the intensity gain in the spot, are estimated. The condition of point focusing is obtained. The conditions for obtaining practically achievable focusing distances are investigated.