Dynamical focusing by bent, asymmetrically cut perfect crystals in Laue geometry

A semi‐analytical approach based on the influence functions of a point source located on the crystal surface has been adopted to show that the focusing ability of cylindrically bent Laue crystals may be strongly enhanced by replacing symmetrically cut crystals with asymmetrically cut crystals. This approach is generally applicable to any distance between the X‐ray source and the focusing bent crystal. A mathematically straightforward method to simplify the derivation of the already known expression of the influence functions in the case of deformed crystals with a constant strain gradient (e.g. cylindrically bent crystals) is also presented. The focusing performances of bent Laue crystals are shown to be strongly sensitive to a small degree of asymmetry.