A diffractometer technique for precise orientation of single crystals

A diffractometer technique for determining the orientation of single crystals is described. The technique is well suited for small spherical or nonabsorbing crystals, as well as for large, extended-face crystals and boules. Since the orientation is determined in a plane perpendicular to the plane of incidence of the diffractometer, the technique does not require an accurate knowledge of the lattice parameter for cubic crystals. The c/a ratio or all cell parameters must, however, be known accurately for crystals of lesser symmetry. It is shown that the orientation can be determined to within 0.005°. Factors affecting the precision of the technique are discussed.