Heat load and anticlastic effect compensation on an ESRF monochromator: An exhaustive ray-tracing study for a meridional-sagittal geometry

Abstract

Undulators installed in third-generation synchrotron radiation facilities will provide photon beams with high brilliance and large power densities. The optical quality of these beams allows, in principle, the use of simpler optical systems for focusing and monochromatization. In practice the performance of the optical elements is the physical limit to the exploitation of these high brilliance beams. In double-crystal monochromators the bending of the first crystal due to the thermal load and the anticlastic effect on the sagittally bent second one are among the main sources of problems on the overall performances. Here we have considered a double-crystal monochromator with a meridionally bent first crystal followed by a sagittally focusing one. We show that this geometry offers correction either of thermal loads and anticlastic distortions, or minimization of the bandpass or tangential focusing. This can be particularly useful on the high-energy range and for sharp Bragg reflections.