Computer Simulation of the Effect of Focusing X Rays by Means of Refractive–Diffractive Lens

The features of focusing X rays using a refractive–diffractive lens (RDL), which is a system of two asymmetrically reflecting crystals with asymmetry factors whose product is equal to unity, and a refractive lens with a large focal length, are theoretically studied. Crystals make it possible to shorten the focal length of the lens by b² times, where b is the asymmetry factor of the second crystal. A detailed numerical simulation of the effect of radiation focusing using the RDL has been performed. The universal computer program XRWP was used, which was created to calculate the effects of coherent X-ray optics. Analytical formulas are obtained for the optimal aperture and radius of curvature of the lens, as well as for the width of the radiation spectrum that can be focused.