R&D toward SuperCDMS at SNOLAB

对星系、超星系团、遥远超新星和宇宙微波背景辐射的观测告诉我们，宇宙中约85%的物质不是由已知粒子构成的。破译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性的重要性。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探测到。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。CDMS目前在明尼苏达州的Soudan使用10公斤的iZIP探测器运行，该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。为了充分利用这一能力，有必要建立一个新的更大、更清洁的实验装置，并将其设在比苏丹深得多的地方，以消除宇宙起源中子背景。这项新实验（SuperCDMS SNOLAB）的基线设计要求在加拿大萨德伯里的SNOLAB进行100公斤锗实验，将iZIP技术应用于直径为100毫米、质量为1.4公斤的探测器上。该奖项为该实验的研究和开发提供支持。它侧重于关键的研发目标：所提议的探测器的测试和表征，对冷硬件和电子设备（用于电离和声子读出的新型HEMT和SQUID）的设计和测试的贡献，以及锗晶体的采购和表征。更广泛的影响：超级cdms实验将产生广泛的影响，其范围将超出暗物质搜索。这项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宇宙学、天文学和工业中得到了许多应用。该项目将有助于培养本科生、研究生和博士后研究人员，使用最前沿的测量技术。SuperCDMS的科学家们将继续参与K-12，他们与教师的合作，以及他们对来自缺乏教育背景的有前途的高中生的支持。

Observations of galaxies, superclusters, distant supernovae, and the cosmic microwave background radiation tell us that ~85% of the matter in the universe is not made of known particles. Deciphering the nature of this 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.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. CDMS is currently operating at Soudan, Minnesota with 10 kg of iZIP detectors, which have already demonstrated a background rejection factor sufficient for zero background operation with several hundred kilogram targets. In order to fully use this capability, it is necessary to build a new larger and cleaner experimental set up and locate it at a much deeper site than Soudan to eliminate the cosmogenic neutron background. The baseline design of this new experiment (SuperCDMS SNOLAB) calls for a 100 kg germanium experiment located at SNOLAB, Sudbury, Canada adapting the iZIP technology to 100 mm diameter detectors of 1.4 kg mass each.This award provides support for Research and Development towards this experiment. It focuses on critical R&D goals: the testing and characterization of the proposed detectors, contribution to the design and testing of the cold hardware and electronics (novel HEMT and SQUID for ionization and phonon readout), and the procurement and characterization of the germanium crystals. Broader impacts: The SuperCDMS experiment will have a broad impact which extends beyond the dark matter search. The technical development will further advance phonon-mediated detectors, which have already found many applications in cosmology, astronomy and industry. The project will contribute to the training of undergraduate and graduate students and postdoctoral researchers, using techniques at the leading edge of measurement technologies. SuperCDMS scientists will continue their involvement in K-12, their collaboration with teachers and their support for promising high school students from underserved backgrounds.