Computer search for layer materials that maximize the reflectivity of X-ray multilayers

Abstract

A database of atomic scattering factors [1] is exhaustively searched for layer materials that potentially maximize collection solid-angle in a multilayer mirror. Maximum attainable performance and corresponding materials are provided at 63 logarithmically spaced wavelengths in the soft X-ray region (6 A < A < 124 Å). Computationally rapid formulas that enable an efficient search are presented. Only a cursory screening is made of material suitability, but a number of possible materials combinations are provided at each wavelength, selected according to several different criteria. Materials-pairs which maximize peak reflectivity often provide high integrated reflectivity as well, but materials rankings by peak and integrated reflectivities show distinct differences