X-ray moire fringes-I
What is it about?
The phenomenon of crystal-diffraction moire fringes is important not only as a most sensitive detecting means of crystal strain, but also from the viewpoint of basic research in crystal-diffraction physics. This paper presents a detailed theoretical description of the diffraction moire fringes in X-rays, where special attention is paid to the fact that the moire fringes are a combination of pure moire interference in crystal lattices and the Pendelloesung intensity oscillation of dynamical crystal diffraction.
Why is it important?
How the interference phase of moire fringes is modulated by the effect of Pendelloesung diffraction-intensity oscillation under the existence of crystal strain is studied in detail. It is revealed that the phase modulation causes an abrupt jump of moire fringes by half a period, irrespective of the associated reciprocal-lattice-vector difference which causes the intrinsic moire fringes.