Performance analysis of a novel monochromator design for the APS SRI-CAT beamline 2-ID-E

Third-generation synchrotron x-ray facilities, such as the Advanced Photon Source, produce x-ray beams that generate a very high heat flux in a very small area. In order to preserve the brilliance of the source, optical components have to be designed to undergo very small thermal deformation (or a change of slope of a flat surface). When an optical component is subjected to a heat load, there will be thermal deformation caused by a temperature increase from the initial state. For a plate-like structure, the temperature difference over the thickness causes bending, and the average temperature increment causes axial deformation. For an optical element, the slope change due to bending is the main reason for the degradation of the performance of the optical component. The change of slope should be limited to a few microradians. There are many ways to control the thermal deformation, such as cryogenic cooling, inclined geometry, liquid-metal cooling, pin-posts or microchannels, using a high-heat-conductivity material, such as diamond, etc. In an accompanying conference paper, an adaptive design technique has been proposed to make use of a novel self-adapted smart structure. Its performance is essentially independent of the heat-load intensity. When such a device is exposed to a heat load, the flat surface remains flat in the area of interest. Therefore this technique can potentially be used to achieve a high precision optical component. Application of the proposed design technique to the monochromator for the SRI-CAT Sector 2 insertion device beamline (Sector 2-ID-E) is explained, and initial analytical results are presented on its performance. copyright 1996 American Institute of Physics