Diffraction of X-rays by Two-dimensional Crystal Lattice

Abstract

IN usual experiments with diffraction of X-rays by crystals, an effect of space-lattice is always observed owing to the penetration of the rays into the depth of the crystal. The thin layers, however, in which one could expect the appearance of diffraction by the two-dimensional lattice, scatter the rays too little, and therefore the experiment becomes impossible. The matter is different in a crystal cleft into very thin layers in such a manner that the orientation of separate layers is not destroyed. This may be well done in mica simply by heating it to red heat and then cooling; but not so well by carefully crushing plates of other crystals. When a thin beam of X-rays passes through such a plate, the effect of two-dimensional lattices will be added, whereas the space effect will be destroyed by the incoherence of waves produced by scattering from incorrectly spaced layers.