Pendellösung Fringes in a Finite Crystal

Abstract

The dynamical theory of electron and X-ray diffraction for a deformed crystal, developed by Takagi, is studied in a finite crystal which includes both the Laue case and the Bragg case by the way on incidence. The integral representations of the crystal wave in a deformed crystal are expressed by the Green functions in a perfect crystal. The diffracted wave in a deformed crystal is given by the sum of the wave field in a perfect crystal and that in a deformed region. The general expressions of the Pendellosung fringes reflected by the interface of the crystal are obtained, and it is shown that there is no essential difference between the Laue case and the Bragg case. The experimental results of reflected Pendellosung fringes by the crystal sides are reported in the X-ray case.