ON THE THEORY OF REFLECTIVITY BY AN X-RAY MULTILAYER MIRROR

A general theory of reflectivity by a perfect X-ray multilayer mirror based on the usage of a recurrent relation is developed. The reflectiv ity is described by the well-known Fresnel formulae which take into ac count jumps of susceptibility at the boundary between the layers. The analytical solution in the frame of the most general dynamical approac h is found and the condition of application of the kinematical approxi mation is discussed. Special attention is paid to the periodic multila yer structure containing two layers of different materials with more t han one pair of these layers in the period.