IntroductionThe third generation synchrotron facilities such as the 7-GeV Advanced Photon Source Project (APS) generate x-ray beams with very high heat loads and heat flux levels. The front-end and beamline components are required to sustain total heat loads of 5 to 15 kW and heat flux levels exceeding 4-00 W/mm2. Grazing geometry and enhanced heat transfer techniques are used in the design of such components to reduce heat flux levels below the 30 W/mm2 level, which is sustainable by the special copper materials routinely used in the component design. Although the resulting maximum surface temperatures can be sustained, the structural stresses and the fatigue issues remain viable concerns for the copper, particularly under brazing or bonding of the parts.Brazing and bonding are almost always utilized in the design of the components, and the drastically lowered yield stress of the annealed copper subjected to bonding temperatures above 400 O C is a real concern. Such materials with reduced post-bonding stress levels easily reach yield point under thermal stresses during ordinary use on the beamline. The resulting plastic deformation in each load cycle may cause low-cycle-fatigue problems. The two common copper materials are OFHC and Glidcop. This paper critically reviews the available literature for low-cycle-fatigue properties of OFHC at the elevated temperatures typically found in synchrotron operations. The high vacuum The submitted manuscript has been authored by a contractor of the U. S. Government under contract No. W-31-104ENG-38. Accordingly, the U. S. Government retains a nonexclusive, rovaltv-free license to oublish or reproduce the published form Of this contribution, or allow others to do SO. for U. S. Government purposes.

The analytical results and design considerations for a cryogenically cooled advanced photon source (APS) silicon monochromator are presented. The high conductivity and low thermal expansion coefficient of silicon at cryogenic temperatures are advantages that are used to solve the high-heat-flux problem from undulator radiation. The APS monochromator features a machined slot with variable thicknesses below the surface. This configuration is designed to reduce absorption by the crystal and decrease the maximum temperature of the crystal. The transmitted power through the crystal is absorbed by a second element that can be cooled by standard cooling techniques. Different parameters and configurations are analyzed to maximize the performance of the monochromator and minimize the total absorbed power by the crystal.

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The pin-fin configuration is widely used in high-heat-flux applications. Recently, the pin-fin design with liquid-metal coolant was also applied to synchrotron-radiation beamline devices. This article investigates the pressure drop in a pin-post crystal with liquid gallium as the coolant. Because the pin-post configuration is a relatively new concept, information in the literature on pin-post mirrors or crystals is rare, and information on the pressure drop in pin-post mirrors with liquid metal as the coolant is even rarer. Because the cross flow in cylinder-array geometry is very similar to that of the pin post, the pressure drop correlation data for the cross flow of fluid with various fluid characteristics or properties through a tube bank are studied so that the results can be scaled to the pin-fin geometry with liquid metal as the coolant. The emphasis of this article is on the influence of two variables on the pressure drop: viscosity and density of fluid. The difference and correlation of the pressure drop between long and short posts and the predication of the pressure drop of liquid metal in the pin-post mirror and comparison with an existing experiment are addressed.

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