Pendellösung fringes in elastically deformed silicon

Abstract

The propagation of pairs of coherent X-ray wavefield beams in a crystal deformed elastically by a uniform temperature gradient, has been studied in the symmetric Laue case by observing interference between the beams when they are superimposed on the X-ray exit surface of the crystal. Information concerning the relative phases of the beams was obtained from the position of Pendellösung fringes in section patterns. The measured change of the relative phase between the two beams was in good agreement with predictions made by the theory ofPenning andPolder. Variations in the magnitude and sign of the deformation, in the X-ray wavelength and in the X-ray structure factor resulted in relative phase changes which were in agreement with the theory.