The measurement of single-crystal lattice parameters using a double-diffraction technique

A modified double-diffraction technique is described for the accurate measurement of lattice parameters of (100) slices of gallium arsenide. The method relies on the selection of appropriate reflexions for producing a pseudo-point of triple diffraction, and the determination of the wavelength necessary to produce such a triple point. Results are presented which show that lattice parameters can be determined rapidly and simply to better than 1 in 10⁵.