Appropriateness of kinematical approach in description of parametric X-radiation of relativistic electron in a single crystal

Contrastive analysis of the formulas for parametric x-ray radiation (PXR) in the dynamic and kinematic approximation is made in the present work. The criteria for the usage of the kinematic formulas are determined on the basis of the dynamic theory. Specifically it was shown that the dynamic effects of PXR must be taken into account even in case of a thin non-absorptive crystal. The published results of the experiment on relativistic electron PXR on Mainz microtron MAMI are discussed. The manifestation of the effect of abnormal photo absorption (the Borrmann effect) in PXR is demonstrated in the experiment.