Ray tracing results for a doubly focusing independent crystal X-ray monochromator

Abstract The need to monochromatize and focus X-rays emitted into appreciable horizontal apertures by storage ring sources (bending magnets and wigglers) leads to the design of focusing monochromators. In order to optimize their design, it is important to understand the combined effect of focusing and diffraction of the flux available at the sample. We analyze here the combined effect of focusing and diffraction for a double-crystal monochromator which is being designed for the Superconducting Wiggler beamline (SCOW) on the ADONE storage ring in Frascati. A double-separated crystal system has been chosen; we study the possibility of obtaining focalization in two steps, by dynamically bending the crystals in order to obtain both tangential and sagittal focusing. Non-focusing and semi-focusing systems have also been considered. The calculations have been performed with the ray tracing program SHADOW. We estimate performances for various focusing geometries and consider the effect of anticlastic curvature.