Angular dependence of secondary emission yield under multiwave X-ray diffraction

General formulae describing angular dependence of secondary emission yield, such as external and internal photoelectrons, fluorescent, thermal diffusion and Compton quanta under multiwave X-ray diffraction in a perfect crystal and in a crystal with a distorted surface layer, are obtained. A scheme for calculation of the perfect crystal under secondary emission detection both from input and output surface is described in detail. The effect of anomalously weak absorption differently manifesting depending on certain conditions is shown to play an essential role under diffraction in Laue-geometry and detection of secondary emission from the output surface of the crystal. Angular dependence of the external photoeffect in this case for 4-wave (220/400/220) diffraction of CuKα radiation in Si is calculated. Intensity of the external photoeffect from the output surface during anomalous passing sharply increases at the presence of an amorphous layer on it with thickness exceeding depth of photoelectron yield