Bragg-(Bragg) m -Laue diffraction and its interference fringe

X-ray rocking curves from side surface of a thin plane-parallel Ge crystal are measured under the condition where the dispersion of the refracted angle is quite large. In the diffracted beams from side surface are observed, which are analysed by using Wagner's approach for Bragg-(Bragg) m -Laue case. The origin of the fringes is explained by the interference between diffraction beams in Bragg-Laue case and that in Bragg-Bragg-Laue case.