Two-period multilayer mirrors for the soft x-ray region

The problem of multilayer mirrors which are capable of reflecting x-ray radiation at two given wavelengths is discussed. Three kinds of two-period multilayers are considered and a comparison of their properties in the soft x-ray region is presented. The scheme of a soft x-ray scanning microscope based on a Schwarzschild objective with a two-period multilayer coating is proposed for chemical microanalysis of biological samples.