Continuous X-ray multiple-beam diffraction with primary Bragg angle from 0 to 90°

The interesting phenomenon of continuous multiple-beam diffraction (MBD) occurring within special crystallographic planes of cubic structures is illustrated for any Bragg angles of the primary reflection. On the one hand, this effect must be avoided in crystal-based X-ray optics or general crystal diffraction experiments that are designed to utilize two-beam diffraction mechanisms, since the MBD process can significantly reduce the diffraction efficiency and the monochromatization quality. On the other hand, the continuous MBD mechanism may have unique practical applications, with the advantage that it can be activated at arbitrary X-ray wavelengths by simply adjusting the azimuthal angle of the primary reflection. A simple mathematical procedure for determining the continuous MBD planes of any primary reflections is developed for optimization of X-ray monochromator designs and for general X-ray characterization of (pseudo)cubic structure crystals using MBD.