We investigate the feasibility of using Bragg-case Kossel lines to measure phase angles of structure-factor amplitudes. Several experimental geometries utilizing a focused beam of synchro- tron radiation to produce a suitable source are proposed. As an example, line profiles and excess integrated intensities are calculated for the [111] and [333] Ga Kossel lines from a GaAs crystal cut parallel to a (111) face. Sources of uncertainty and applicability of this technique are also discussed. The analysis shows that by using this method it should be possible to measure phase angles to within a few degrees, despite ‘‘smearing’’ of the line profiles due to angular resolution and the inherent linewidth of the emitted x rays.

• Received 4 June 1984

DOI:https://doi.org/10.1103/PhysRevB.31.743