Liquid gallium cooling of silicon crystals in high intensity photon beams

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1140968· OSTI ID:5819602

Smither, R K; Forster, G A; Bilderback, D H; Bedzyk, M; Finkelstein, K; Henderson, C; White, J; Berman, L E; Stefan, P; Oversluizen, T; others, and

The high-brilliance, insertion-device-based photon beams of the next generation of synchrotron sources (Argonne's APS and Grenoble's ESRF) will deliver large thermal loads (1--10 kW) to the first optical elements. Considering the problems that present synchrotron users are experiencing with beams from recently installed insertion devices, new and improved methods of cooling these first optical elements, particularly when they are diffraction crystals, are clearly needed. A series of finite element calculations were performed to test the efficiency of new cooling geometries and various cooling fluids. The best results were obtained with liquid Ga metal flowing in channels just below the surface of the crystal. Ga was selected because of its good thermal conductivity and thermal capacity, low melting point, high boiling point, low kinetic viscosity, and very low vapor pressure. Its very low vapor pressure, even at elevated temperatures, makes it especially attractive in UHV conditions. A series of experiments were conducted at CHESS in February of 1988 that compared liquid gallium-cooled silicon diffraction crystals with water-cooled crystals. A six-pole wiggler beam was used to perform these tests on three different Si crystals, two with new cooling geometries and the one presently in use. A special high-pressure electromagnetic induction pump, recently developed at Argonne, was used to circulate the liquid gallium through the silicon crystals. In all experiments, the specially cooled crystal was used as the first crystal in a two crystal monochromator. An infrared camera was used to monitor the thermal profiles and correlated them with rocking curve measurements. A second set of cooling experiments were conducted in June of 1988 that used the intense, highly collimated beam from the newly installed ANL/CHESS undulator.

• Research Organization: Argonne National Laboratory, Argonne, Illinois 60439 (US); Cornell University, Ithaca, New York 14853; Brookhaven National Laboratory, Upton, New York 11973
• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 5819602
• Journal Information: Rev. Sci. Instrum.; (United States), Vol. 60:7
• Country of Publication: United States
• Language: English

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43 PARTICLE ACCELERATORS
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CORNELL 10-GEV SYNCHROTRON
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GALLIUM
PHOTON BEAMS
PHYSICAL PROPERTIES
POWER RANGE 1-10 KW
SILICON
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430400* - Particle Accelerators- Storage Rings