NEUTRON-DIFFRACTION IN FLAT AND BENT MOSAIC CRYSTALS FOR ASYMMETRIC GEOMETRY

Exact solutions of power transfer equations for plane-parallel and ben t crystals in symmetric and asymmetric Bragg and Laue geometries are o btained, for the nonabsorbing case. Conceptual and mathematical errors in the solutions for asymmetric diffraction given by Bacon & Lowde [A cta Cryst. (1948), 1, 303-314] are pointed out. A very significant res ult is that, for asymmetrical Laue geometry, over 50% reflecting power is proved to be possible when b < 1. The integrated reflecting power and expressions for the optimum value of the curvature radius for bent mosaic crystals in the Bragg and Laue cases are also given.