PIRE: Advanced Germanium Detectors and Technologies for Underground Physics

PI：梅东明（南达科他大学）合作PI：哈兰·哈里斯（德克萨斯农工大学）约翰·威尔克森（北卡罗来纳大学）非技术摘要：了解宇宙在基本层面上的运作方式是在地球上利用其力量的关键。对引力现象的观测表明，宇宙中80%的物质是暗物质（DM）。发现暗物质需要新的直接探测策略来探测暗物质与普通物质之间的非引力相互作用。除了暗物质，中微子在理解宇宙方面也发挥着重要作用。中微子质量的发现在我们宇宙中观察到的物质相对于反物质的不对称性和假设的中微子性质之间建立了一个潜在的诱人联系。如果中微子本身就是反粒子，这或许可以解释物质比反物质更普遍的现象。要回答这个问题，实验上唯一可行的方法是寻找中微子双β (0νββ)衰变，这是一种被提议的核衰变形式。相干弹性中微子核散射（CE&#957；NS）的观测表明了中微子的几个重要性质。测试这些特性可以让我们更好地理解宇宙的起源和演化。因此，暗物质的性质和中微子的关键性质是基础物理学中最重要的两个问题。PIRE-锗材料和探测器进步研究联盟（PIRE- GEMADARC）是一个全球合作伙伴关系，旨在加速用于吨级DM和0的研究和开发的锗（Ge）材料平台。在培养下一代科学家的同时进行衰变实验。pierre - gemadarc还开发创新方法来构建新型低阈值和高分辨率锗探测器，应用于国土安全，环境监测和医学成像。技术摘要：pierre - gemadarc利用美国、加拿大、中国、德国和台湾的11家机构的研究专长、培训能力和世界知名的设施。具体而言，pierre - gemadarc将：(1)推进区域细化和晶体生长技术，以保证大尺寸锗（LGe）探测器级晶体的纯度和适当的梯度；(2)研制LGe探测器，实现DM和CE&amp；#957的低能量阈值；0νβ&#946；衰变;(3)通过更好地了解电荷收集效率、背景还原方法和系统不确定度来提高探测器性能；(4)加强对该领域青年科学家的教育和培训。直接检测DM并观察0&amp；#957;β&#946；衰变需要很深的地下实验室，极其纯净的探测器，以及成熟的晶体生长专业知识。​同样重要的是，该联盟通过其综合研究和教育计划培养下一代多样化的科学家和工程师。在这个为期五年的奖项结束时，该联盟将培养170多名本科生和研究生以及K-12教师，加上5名博士后，其中大多数将具有实际的国际研究经验，其中很大一部分将来自代表性不足的群体。该联盟的综合青年教师发展计划将为六名早期职业教师做好学术领导准备。

PI: Dongming Mei (University of South Dakota)co-PIs: Harlan Harris (Texas A&M University)John Wilkerson (University of North Carolina)Nontechnical abstract:Understanding how the Universe works at its fundamental level is key to harnessing its power here on Earth. Observations of gravitational phenomena indicate that 80% of the matter in the Universe is dark matter (DM). Novel direct-detection strategies to probe non-gravitational interactions between DM and ordinary matter are needed to discover DM. In addition to DM, neutrinos also play an important role in understanding the Universe. The discovery of neutrino mass has created a potential tantalizing connection between the observed asymmetry of matter over antimatter in our Universe and postulated neutrino properties. If neutrinos are their own anti-particles, this might offer an explanation of the prevalence of matter over anti-matter. The only experimentally feasible way to answer this question is to look for neutrinoless double-beta (0νββ) decay, a proposed form of nuclear decay. Observation of coherent elastic neutrino-nucleus scattering (CEνNS) indicates several important properties of neutrinos. Testing these properties could lead to a better understanding of the origin and evolution of the Universe. Therefore, the nature of dark matter and key properties of neutrinos are two of the most important questions in fundamental physics. PIRE-GErmanium Materials And Detectors Advancement Research Consortium (PIRE- GEMADARC) is a global partnership created to accelerate the germanium (Ge) material platform used in research and development for ton-scale DM and 0νββ decay experiments while educating the next generation of scientists. PIRE-GEMADARC also develops innovative approaches to constructing new types of low threshold and high-resolution Ge detectors with applications in homeland security, environmental monitoring, and medical imaging. Technical abstract:PIRE-GEMADARC leverages the research expertise, training capabilities, and world-renowned facilities of eleven institutions in the United States, Canada, China, Germany, and Taiwan. Specifically, PIRE-GEMADARC will: (1) advance techniques in zone refinement and crystal growth to guarantee the purity and appropriate gradient of large-size Ge (LGe) detector-grade crystals; (2) develop LGe detectors to achieve low energy thresholds for DM and CEνNS detection and better particle discrimination for 0νββ decay; (3) improve detector performance by gaining a better understanding of charge collection efficiency, background reduction methods, and systematic uncertainties; and (4) enhance education and training for young scientists in the field. Direct detection of DM and observation of 0νββ decay requires deep underground laboratories, extremely pure detectors, and well-established expertise in crystal growth. This Consortium provides access to the deepest underground laboratories - SNOLAB (Canada) and China Jinping Underground Laboratory (China), and includes world-class international expertise in developing Ge detectors from Max-Planck-Institut für Physik (Germany) and the Institute of Physics, Academia Sinica (Taiwan). Equally important is the work of the Consortium to develop the next generation of diverse scientists and engineers through its integrated research and education program. At the end of this five-year award, the Consortium will have trained more than 170 undergraduate and graduate students and K-12 teachers, plus 5 postdoctoral fellows - a majority of whom will have practical international research experiences, and a significant fraction of which will be from underrepresented groups. The Consortium's comprehensive Junior Faculty Development plan will prepare six early career faculty members for academic leadership.