Concentrators of soft X-rays

The properties of axisymmetric and cylindrical optical concentrations in the wavelength region where all the substances possess low reflectivity are considered. The losses related to radiation leaving the system through side faces and reflective walls are found, and the ultimate efficiency of the concentrator is determined. On the basis of available data on optical constants the dependence of the efficiency on the choice of the reflective coating material is analyzed. The role of the roughness of the reflective surface is discussed and the principal requirements on the accuracy of concentrator fabrication are stated