RII Track-4: Operating High Purity Germanium Detectors in Liquid Scintillator

中微子是自然界中大量产生的亚原子粒子。研究幽灵中微子的内在性质一直是一个挑战，因为它们可以通过仪器和材料，几乎没有任何相互作用。由于技术的进步和科学界的长期承诺，最近的突破揭示了中微子的关键但意想不到的性质，例如中微子具有非零质量的事实。有关中微子的新知识可以探索自然界的基本对称性，并可能揭示宇宙中物质超过反物质的关键谜团。太阳系外的中微子也是携带宇宙信息的信使之一，这些信息可以让我们对宇宙有一个更完整的了解。这项提议旨在开发能够促进实验的技术，以加深我们对中微子的理解，包括探索非零中微子质量的起源。它还将在新的方向上推动南达科他大学和洛斯阿拉莫斯国家实验室之间的合作。美元集团获得的变革性新专业知识将增强该集团在地下科学与工程领域的研究能力，地下科学与工程是南达科他州高价值的研究领域之一，并与南达科他州的目标工业部门保持一致。美国国际和平研究所计划访问LANL，开发使用液态AAR(LAR)的主动否决技术，旨在为拟议的大型富集锗无中微子双β衰变实验(LENGUG)项目。主办方和主办方都是传奇的合作者。联想的合作旨在开发一个分阶段的、基于Ge-76的无中微子双β衰变(NLDBD)实验计划，具有发现10e28年后半衰期的潜力。联想公司将在大容量的LAR中操作多达一吨的高纯度锗探测器。Lar盾牌作为一种积极的否决权，在消除NLDBD的广泛背景方面非常强大。具体地说，PI和学员将与LANL研究人员合作，将LANL现有的低温恒温器改造成具有净化能力和光收集仪器的LAR测试台。我们将直接将高纯度的锗探测器浸入并操作在液氮中。通过美元和LANL的合作研究，我们可以评估集成系统的整体性能，并加深我们对LAR主动否决的背景拒绝性能的理解。除了推进传奇项目的准备工作外，这项研究奖学金还将为PI提供液体闪烁体技术方面的专业知识，并使PI能够长期维持他在实验中微子物理方面的职业生涯。LANL的硬件基础设施和技术专长的结合对于开展拟议的活动至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Neutrinos are subatomic particles abundantly produced in Nature. It has been challenging to investigate the intrinsic properties of the ghostly neutrinos, because they can pass through instruments and materials with barely any interactions. Thanks to advancements of technology as well as long-term commitment of the science community, recent breakthroughs have revealed critical yet unexpected properties of neutrinos, such as the fact that neutrinos have non-zero masses. New knowledge on neutrinos can probe fundamental symmetries in Nature and could shed light on the key mystery of matter-over-antimatter excess in the universe. Extrasolar neutrinos are also one of the messengers carrying information about the universe that can lead us to a more complete picture of the universe. This proposal aims at developing techniques that could facilitate experiments to deepen our understanding of neutrinos, including probing the origin of non-zero neutrino masses. It will also advance the collaboration between the University of South Dakota (USD) and Los Alamos National Laboratory (LANL) in new directions. The transformative new expertise gained by the USD group will enhance the group's research capability in Underground Science and Engineering, one of the high value research areas and assets aligned with target industry sectors for South Dakota.The PI at USD plans to visit LANL to develop active veto techniques employing liquid argon (LAr), intended for the proposed Large Enriched Germanium Experiment for Neutrinoless double-beta Decay (LEGEND) project. Both the home and host groups are LEGEND collaborators. The LEGEND collaboration aims to develop a phased, Ge-76 based neutrinoless double-beta decay (NLDBD) experimental program with discovery potential at a half-life beyond 10e28 years. LEGEND will operate up to one tonne of high-purity germanium detectors inside a large volume of LAr. The LAr shield serves as an active veto that is powerful in eliminating a wide range of backgrounds for NLDBD. Specifically, the PI and trainees will collaborate with LANL researchers to convert an existing cryostat at LANL into a LAr test stand with purification capability and light collection instrumentation. We will directly immerse and operate high-purity germanium detectors inside liquid argon. Through this collaborative research between USD and LANL, we can evaluate the overall performance of the integrated system and improve our understanding of the background rejection performance of a LAr active veto. In addition to advancing the preparation for the LEGEND project, this Research Fellowship will arm the PI with expertise on liquid scintillator technologies and enable the PI to sustain his career in experimental neutrino physics in the long-term. A combination of hardware infrastructure and technical expertise at LANL is essential to carry out the proposed activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.