X-Ray Crystal Collimators Using Successive Asymmetric Diffractions and Their Applications to Measurements of Diffraction Curves. I. General Considerations on Collimators

General considerations are given on the intensity distributions obtained from various types of the collimator system made of a monolithic crystal, in which asymmetric Bragg-case diffractions take place successively by crystal components, so that an exploring beam of an extremely narrow angular spread of a few hundredths of the range of total reflection for the symmetric-case diffraction can be obtained. Type I and II of collimators use highly asymmetric diffractions; in type II the neighbouring components are inclined to each other to avoid deviation of the angular ranges of total reflection for two components. In type III the components are purposely arranged so that the angular ranges of total reflections for the neighbouring components overlap only partially. It is shown by calculations that an angular spread of about 0.1'' is obtained by collimators of the above types using 422 diffraction of silicon with CuKα.