Answer to Question #228306 in Optics for Saiqa

Question

How is the diffraction of X-rays by crystals??

Answer 1

The X-ray diffraction work pioneered by Max von Laue resulted in identifying the geometry and spacing of atoms within crystals. Certain of these crystals have a cubic pattern, in which the atoms are placed at the corners of cubes in a repetitive pattern as shown in Fig. a. One can also consider that the atoms of such crystals align in equally spaced planes, a side view of which is shown in Fig. b. In each atom is treated as a point that can reflect part of an incoming beam of X-rays, the figure implies that the path differences of X-rays reflected from different atoms will dictate whether the reflected rays interfere constructively or destructively. Furthermore, since the atoms constitute numerous points of reflection, the interference is similar to that of a diffraction grating with many slits, which results in a well-resolved constructive interferences for different wavelength radiations, with negligible contribution from other interferences.