Cryogenic Detectors for Next-Generation Physics Experiments

多次天文观测已经证实，宇宙中大约85%的物质不是由已知粒子构成的。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至关重要。一个主要的假设是，它是由大爆炸后瞬间产生的弱相互作用大质量粒子（wimp）组成的。如果wimp是暗物质，那么它们在我们星系中的存在可以通过位于地下深处的探测器的原子核散射来检测，以帮助排除宇宙射线造成的背景。低温暗物质搜索（CDMS）合作率先使用低温声子介导的探测器来探测核上罕见的wimp散射，并将它们与背景区分开来。这项工作将产生广泛的影响，超出了暗物质的搜索。该技术的发展将进一步推动声子介导探测器的发展，声子介导探测器已经在科学和技术上找到了许多应用。CDMS目前正在明尼苏达州的Soudan地下实验室使用10公斤的新型iZIP探测器进行操作，这些探测器已经证明了足以对数百公斤目标进行零背景操作的背景抑制因子。与其他技术相比，SuperCDMS技术提供的高本底抑制和污染控制具有显著优势，对低质量暗物质具有出色的灵敏度，对高质量WIMPS具有竞争性灵敏度，并且在单个实验中具有多目标互补性。SCU团队将继续在斯坦福大学的测试和表征工作中发挥核心作用，包括上线、维护、升级和/或操作三台斯坦福冰箱。PI将投入大约25%的时间用于可能影响未来实验的长期研发，例如基于squid读出的码分多路复用领域。这笔拨款将为几个级别的学生提供研究和培训机会，以进行一个实验，该实验将解决现代科学中最基本的问题之一，即暗物质的本质。SCU本科生将主要完成探测器制造、测试和优化领域的CDMS实验室工作。

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.