Acquisition of a Helium 3 Refrigerator for Synchrotron X-ray Studies

9625919 Chan X-ray scattering provides an extremely powerful probe of the microscopic properties of condensed materials systems. The proposed 3He refrigeration system and associated electronics and gas handling components will allow us to apply X-ray scattering techniques to materials systems at low temperatures, in particular quantum liquids. Such capabilities are not available at any synchrotron x-ray source in the world. Thus, this 3He refrigeration system will provide a unique and valuable facility. The proposed refrigeration system will be initially used for the study of disorder and impurities in helium mixtures. This disorder can be introduced either through the introduction of annealed impurities, such as 3He in 4He, or confinement in porous glasses, such as vycor or aerogel, or both. The presence of disorder can have profound effects on the critical behavior, transport properties and phase separation of 3He-4He mixtures. It can also modify the microscopic structure, as reflected in the pair correlation function of the atoms. The research studies will directly address these microscopic issues using x-ray scattering. The research will make use of either the National Synchrotron Light Source currently operating at Brookhaven National Laboratory or the Advanced Photon source which is under construction at Argonne National Laboratory. The proposed refrigeration system will be designed with sufficient flexibility to allow it to be used on a variety of instruments at either of these sources. %%% This project will have broad scientific impact to the field of low temperature materials research and will provide unique capability to the important area of x-ray scattering for the advancement of characterization of materials of economic importance. ***