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

小行星9625919 X射线散射提供了一个非常强大的探测凝聚材料系统的微观性质。 拟议的3He制冷系统和相关的电子和气体处理组件将使我们能够在低温下将X射线散射技术应用于材料系统，特别是量子液体。 这种能力在世界上任何同步加速器X射线源都不可用。 因此，该3He制冷系统将提供独特且有价值的设施。 所提出的制冷系统将首先用于氦混合物中的无序和杂质的研究。 这种无序可以通过引入退火杂质（如4He中的3He）或限制在多孔玻璃（如vycor或气凝胶）中或两者来引入。 无序的存在会对3He-4He混合物的临界行为、输运性质和相分离产生深远的影响。 它还可以改变微观结构，如原子的对相关函数所反映的那样。 这些研究将使用X射线散射直接解决这些微观问题。 这项研究将利用布鲁克海文国家实验室目前运行的国家同步加速器光源或阿贡国家实验室正在建设的先进光子源。 拟议的制冷系统的设计将具有足够的灵活性，使其能够在这些来源中的任何一个来源的各种仪器上使用。 该项目将对低温材料研究领域产生广泛的科学影响，并将为X射线散射的重要领域提供独特的能力，以促进具有经济重要性的材料的表征。 ***

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. ***