Thermal optimization of a high-heat-load double-multilayer monochromator

Finite-element analysis is used to study the thermal deformation of a multilayer mirror due heat load from undulator beam at low-emittance synchrotron source, specifically ESRF-EBS upgrade beamline EBSL-2. The energy bandwidth double-multilayer monochromator larger than that relevant harmonic, such considerable portion reflected. Consequently, absorbed power non-uniformly distributed on surface. geometry substrate optimized minimize thermally induced slope errors. We distinguish between bending with constant curvature leads astigmatic focusing or defocusing and residual For EBSL-2 system grazing angles ? 0.2 0.4°, meridional sagittal focal lengths down 100 m 2000 m, respectively, are found. Whereas can be tuned by varying depth `smart cut', it found has little effect In both planes they 0.1–0.25 µrad. direction, however, drastically reduced `foregiveness factor', sin(?). Optimization without considering reflected yields an incorrect cut'. resulting in turn parasitic order m.