Finite Element Analysis of the Distortion of a Crystal Monochromater from Synchrotron Radiation Thermal Loading,
CALIFORNIA UNIV BERKELEY LAWRENCE BERKELEY LAB
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The first crystal of the Brown-Hower x ray monochromator of the LBL-EXXON 54 pole wiggler beamline at Stanford Synchrotron Radiation Laboratory SSRL is subjected to intense synchrotron radiation. To provide an accurate thermalstructural analysis of the existing monochromator design, a finite element analysis FEA was performed. A very high and extremely localized heat flux is incident on the Si 220 crystal. The crystal, which possesses pronouncedly temperature dependent orthotropic properties, in combination with the localized heat load, make the analysis ideally suited for finite element techniques. Characterization of the incident synchrotron radiation is discussed, followed by a review of the techniques employed in modeling the monochromator and its thermalstructural boundary conditions. The results of the finite element analysis, three dimensional temperature distribution, surface displacements and slopes, and stresses, in the area of interest, are presented. Lastly, the effects these results have on monochromator output flux and resolution are examined.