Collaborative Research: Combating Cosmogenic Argon Isotopes in LEGEND

合作研究：对抗《LEGEND》中的宇宙成因氩同位素

• 批准号: 2111176
• 负责人: Matthew Green
• 金额: $ 51万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111176&HistoricalAwards=false
• 关键词: Collaborative; Research; Combating; Cosmogenic; Argon; Collaborative; Research; Combating; Cosmogenic; Argon

Neutrinos are electrically neutral and have non-zero mass, although their mass is very small. These properties raise the possibility that neutrinos are their own antiparticles (i.e. Majorana particles). If a neutrino is, indeed, its own anti-particle then this would shed light on the reason why matter dominates over antimatter in our universe and would point to new physics at energies far beyond those of our largest collider-accelerators. If neutrinos are Majorana particles, then double-beta decay without the simultaneous emission of neutrinos, or zero-neutrino double-beta decay (0νββ), becomes possible. The PI will search for 0νββ in an upcoming experiment. The ultra-rare nature of the decay, and the extreme sensitivity sought by the experiment, require backgrounds to be strictly controlled. For example, the experiment must be constructed with ultra-pure materials, be deployed underground, and make use of advanced techniques to discriminate signal from background.The LEGEND experiment will use germanium detectors enriched in the isotope Ge-76 to conduct a search for 0νββ. LEGEND hopes to achieve 10 ton-years of exposure with backgrounds reduced by over an order-of-magnitude compared to what has been previously demonstrated. This project aims to address the leading background contribution to the LEGEND experiment. For example, the presence of trace amounts of radioactive Ar-42 in the liquid argon bath in which LEGEND’s Ge detectors will operate will interfere with the counting of real 0νββ events. The PI will perform measurements in liquid argon in order to develop tools to accurately estimate the impact of this source of background and also develop analysis tools to remove it from the data. The PI also aims to develop a robust and validated background model that can be integrated into the LEGEND data processing framework. The goal is to produce reliable energy spectra which can be used for background estimation and fitting, and accurately model pulse shape discrimination techniques which can be used to suppress backgrounds arising from Ar-42.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.

中微子是电中性的，尽管质量很小，但具有非零的质量。这些特性提出了神经元是其自身的抗颗粒（即主要颗粒）的可能性。如果确实是神经元自己的抗颗粒，那么这将阐明为什么物质在我们宇宙中占主导地位的原因，并且会指向远远超出我们最大的撞机器 - 加速器的新物理学。主要颗粒，然后是双β衰变，没有神经元同时发射，或零中性双β衰减（0νββ）的可能性。 PI将在即将进行的实验中搜索0νββ。衰减的超稀有性质以及实验的极端灵敏度SCART需要严格控制背景。例如，必须用超校型材料构建实验，在地下部署，并利用先进的技术从背景中区分信号。传奇实验将使用富含同位素GE-76中的锗检测器来进行0νββ的搜索。传奇人物希望与先前证明的相比，能够实现10吨年的曝光，背景降低超过了魔力。该项目旨在解决对传奇实验的主要背景贡献。例如，在液体氩气浴中存在痕量的放射性AR-42，其中传说的GE检测器将运行，将干扰实际0νββ事件的计数。 PI将在液体氩气中进行测量，以开发工具以准确估计这种背景的影响，并开发分析工具以将其从数据中删除。 PI还旨在开发一个可靠且经过验证的背景模型，该模型可以集成到传奇数据处理框架中。目的是生产可靠的能源光谱，可用于背景估计和拟合，并准确地模拟脉冲形状歧视技术，可用于抑制AR-42引起的背景。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识绩效和更广泛的影响审查的评估来通过评估来获得的支持。