Photon beams from the insertion devices of the Argonne synchrotron facility (APS) have very high total powers, which in some cases will exceed 10 kW, spread over a few cm2. These high heat loads require special cooling methods to keep them from degrading the quality of the photon beam. A set of finite element analysis calculations were made in three dimensions to determine the temperature distributions and thermal stresses in a single crystal of silicon with heat loads of 2 kW to 20 kW. Different geometric arrangements and different cooling fluids (water, gallium, oil, Na, etc.) were considered. The two best fluids for room temperature operation were found to be water and liquid gallium metal. The variation in temperature across the face of the crystal and the distortion of the surface was at least a factor of two less for the gallium cooling case than for the water cooling case. The water cooling was effective only for very high flow rates. Efficient cooling and the very low vapor pressure for liquid gallium (less than 10−12 Torr at 100°C) make liquid gallium a very attractive cooling fluid for high vacuum synchrotron applications. A small electromagnetic induction pump for liquid Ga was built to test this cooling method. The new system is portable, controls the output temperature of the Ga and can handle heat loads of 10 kW. 13 figs.

The installation of insertion devices at existing synchrotron facilities around the world has stimulated the development of new ways to cool the optical elements in the associated x-ray beamlines. Argonne has been a leader in the development of liquid metal cooling for high heat load x-ray optics for the next generation of synchrotron facilities. The high thermal conductivity, high volume specific heat, low kinematic viscosity, and large working temperature range make liquid metals a very efficient heat transfer fluid. A wide range of liquid metals were considered in the initial phase of this work. The most promising liquid metal cooling fluid identified to date is liquid gallium, which appears to have all the desired properties and the fewest number of undesired features of the liquid metals examined. Besides the special features of liquid metals that make them good heat transfer fluids, the very low vapor pressure over a large working temperature range make liquid gallium an ideal cooling fluid for use in a high vacuum environment. A leak of the liquid gallium into the high vacuum and even into very high vacuum areas will not result in any detectable vapor pressure and may even improve the vacuum environment as the liquid gallium combines with any water vapor or oxygen present in the system. The practical use of a liquid metal for cooling silicon crystals and other high heat load applications depends on having a convenient and efficient delivery system. The requirements for a typical cooling system for a silicon crystal used in a monochromator are pumping speeds of 2 to 5 gpm (120 cc per sec to 600 cc per sec) at pressures up to 100 psi.

This compendium summarizes the core principles and practical applications of a brand-new advanced chip cooling category — liquid metal cooling. It illustrates the science and art of room temperature liquid metal enabled cooling for chip, device and system. The concise volume features unique scientific and practical merits, and clarified intriguing liquid metal coolant or medium behaviors in making new generation powerful cooling system.With both uniquely important fundamental and practical values, this useful reference text benefits researchers to set up their foundation and then find new ways of making advanced cooling system to fulfil the increasingly urgent needs in modern highly integrated chip industry.

The development of synchrotron radiation (SR) as a research tool was driven largely by the needs of materials scientists and solid-state physi cists. However, the availability of SR has extended significantly the capa bility of scientists who study biological structure with radiation. This volume contains some of the results reported at a symposium held at Brookhaven National Laboratory in May 1988 to discuss the application of synchrotron radiation to structural biology. We are grateful for financial support from the u. s. Department of Energy, the National Institutes of Health, Genentech, Inc., Blake Indus tries, Inc., Evans and Sutherland Co., The Upjohn Company, Eli Lilly and Company, Enraf-Nonius Service Corp., and Associated Universities, Inc. We warmly thank Ms. Nancy Siemon for her tireless efforts with correspondence and the manuscripts for this symposium volume. Symposium Committee: Robert M. Sweet, Chair Malcolm S. Capel Benno P. Schoenborn John C. Sutherland Elizabeth C. Theil Stephen W. White Avril D. Woodhead Helen Z. Kondratuk, Coordinator v CONTENTS An Introduction to the Symposium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 R. M. Sweet SYMPOSIUM LECTURE Developments in X-ray Technology and Their Contribution to Structural Biology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 H. E. Huxley SOME OF THE SYNCHROTRON FACILITIES FOR BIOLOGICAL STRUCTURAL STUDIES MacChess - A Macromolecular Diffraction Resource at the Cornell High Energy Synchrotron Source . . . . . . . . . . . . . . . . . . . 15 W. Schi1dkamp, K. Moffat, B. Batterman, D. Bilderback, T-Y. Teng, A. LeGrand and D. Szebenyi Facilities Available for Biophysics Research at the Stanford Synchrotron Radiation Laboratory. . . . . . . . . . . . . . . . . . . . . 19 R. P."

Publishes papers reporting on research and development in optical science and engineering and the practical applications of known optical science, engineering, and technology.