Cryogenic Detectors for Next-Generation Physics Experiments

多项天文观测证实，宇宙中约85%的物质不是由已知粒子组成的。破译这种所谓的暗物质的本质对宇宙学、天体物理学和高能粒子物理学具有根本的重要性。一个主要的假设是，它是由相互作用很弱的大质量粒子组成的，这些粒子是在大爆炸后不久产生的。如果WIMP是暗物质，那么它们在我们银河系中的存在可能是通过位于深处的探测器中原子核的散射来检测到的，以帮助排除由于宇宙射线造成的背景。低温暗物质搜索(CDMS)合作开创了使用低温声子介导的探测器来探测WIMP在原子核上罕见的散射并将它们与背景区分开来的先河。这项工作将产生超越暗物质搜索的广泛影响。这些技术的发展将进一步推动声子介导的探测器的发展，后者已经在科学技术中得到了许多应用。CDMS目前在明尼苏达州的Soudan地下实验室运行，使用10公斤的新型iZip探测器已经证明，对于数百公斤的目标，背景抑制系数足以进行零背景操作。与其他技术相比，SuperCDMS技术提供的高背景抑制和污染控制提供了显著的优势，提供了对低质量暗物质的卓越灵敏度、对高质量WIMPS的竞争灵敏度以及在单个实验中的多目标互补性。SCU团队将继续在斯坦福大学的测试和鉴定工作中发挥核心作用，包括上线、维护、升级和/或运营三台斯坦福大学的冰箱。国际和平研究所将把大约25%的时间用于可能影响未来实验的长期研发，例如，在基于鱿鱼的读数的码分多工领域。这笔拨款将支持多个级别的学生进行研究和培训机会，以开展一项实验，该实验将解决现代科学最基本的问题之一--暗物质的性质。SCU本科生将完成CDMS的实验室工作，主要是在探测器制造、测试和优化领域。

Multiple astronomical observations have established that about 85% of the matter in the universe is not made of known particles. Deciphering the nature of this so-called Dark Matter is of fundamental importance to cosmology, astrophysics, and high-energy particle physics. A leading hypothesis is that it is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced moments after the Big Bang. If WIMPs are the dark matter, then their presence in our galaxy may be detectable via scattering from atomic nuclei in detectors located deep underground to help reject backgrounds due to cosmic rays.The Cryogenic Dark Matter Search (CDMS) Collaboration has pioneered the use of low temperature phonon-mediated detectors to detect the rare scattering of WIMPs on nuclei and distinguish them from backgrounds. This work will have a broad impact which extends beyond the dark matter search. The technical developments will further advance phonon-mediated detectors, which have already found many applications in science and technology.CDMS is currently operating at the Soudan underground laboratory in Minnesota with 10 kg of novel iZIP detectors that have already demonstrated a background rejection factor sufficient for zero background operation with several hundred kg targets. This high background rejection and control of contamination that the SuperCDMS technology offers provide significant advantages compared to other technologies, providing excellent sensitivity to low mass dark matter, competitive sensitivity to high-mass WIMPS, and multiple-target complementarity in a single experiment. The SCU team will continue to play a central role in the testing and characterization efforts at Stanford, including bringing online, maintaining, upgrading and/or operating three Stanford fridges. The PI will devote approximately 25% of her time on long-term R&D that could impact a future experiment, for example in the area of code-division-multiplexing for SQUID-based readoutsThis grant will support research and training opportunities for students at several levels to work on an experiment that will address one of the most fundamental problems of modern science, the nature of dark matter. SCU undergraduates will complete laboratory-based work for CDMS primarily in the areas of detector fabrication, testing and optimization.