| A novel mounting and cryogenic coolant manifold system to minimize sub-micron mounting strains and improve the sealing of the liquid nitrogen coolant in the ultra-high-vacuum environment of high-intensity x-ray beamlines is proposed. A unique method to accurately simulate the complex interaction of the x-ray beam with the silicon monochromator and the subsequent thermal distortion is presented.; Silicon crystal monochromators at cryogenic temperatures have been used with great success at third generation synchrotron radiation sources. At Argonne's Advanced Photon Source, APS, the unique characteristics of silicon at liquid nitrogen temperatures (∼80°K) have been leveraged to significantly minimize the thermally induced distortions on beamline optical components. Non-linear finite element analysis (FEA) simulations, which take into consideration the highly sensitive changes in temperature due to the coefficient of thermal expansion and thermal conductivity were investigated.; The thermal-stress problem was performed and compared with experimental measurements, made at the APS sector 1 insertion device (1-ID) beamline. Based on the FEA results of the current monochromator design, a unique mounting mechanism that improves the sealing of the liquid nitrogen coolant without inducing sub-micron strains was designed, analyzed and tested. In general, the use of the finite element method in predicting the overall thermal and structural response of precision optical components with a depth-dependent, high-flux thermal load is shown to be an effective predictive design tool. This research is supported by the U.S. Department of Energy, BES-Material Science, under Contract No. W-31-109-ENG-38. |
