DUSEL R&D towards a tonne scale Ge neutrinoless double-beta decay experiment

杜塞尔R

• 批准号: 0810311
• 负责人: John Wilkerson
• 金额: $ 25万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0810311&HistoricalAwards=false
• 关键词: DUSEL; R& towards; tonne; scale

With the realization that neutrinos are massive, there is an increased interest in investigating their intrinsic properties. Understanding the neutrino mass generation mechanism, the absolute neutrino mass scale and the neutrino mass spectrum are some of the main focuses of future neutrino experiments. Experimental evidence of neutrinoless double-beta decay (NDBD) would definitively establish the Majorana nature of neutrinos while also providing information about the absolute neutrino mass. This award will enable the Majorana Collaboration to carry out R&D activities related to the development of the proposed Majorana Demonstrator, a prototype Ge detector array that aims to prove the feasibility of building a future 1-tonne Ge NDBD experiment. The research would be conducted by the collaboration in two distinct areas: Ge detector development and the production and assay of ultra-low background materials. Building a NDBD experiment with the ability to probe neutrino mass in the inverted hierarchy region requires the combination of a large detector mass sensitive to NDBD, on the order of 1-tonne, and unprecedented background levels, on the order of or less than 1 count per year in the NDBD signal region. They plan to deploy and evaluate two different Ge detector technologies, one based on P-type material and the other on N-type. Many of the initial suite of experiments being considered for DUSEL will directly benefit from the availability of ultra-clean materials with extremely small amounts of U and Th. Verifying the purity of materials requires sensitivities at the sub microBq/kg level. The development of enhanced sensitivity inductively coupled plasma mass spectrometry will benefit a broad set of applications and future experiments. The Ge detector development will benefit applications that require very low energy thresholds while also providing reduced backgrounds from associated detector components.

随着人们认识到中微子的质量，人们对研究它们的内在性质越来越感兴趣。中微子质量产生机制、中微子绝对质量标度和中微子质量谱是未来中微子实验的重点。无中微子双β衰变（NDBD）的实验证据将确定中微子的马约拉纳性质，同时也提供关于中微子绝对质量的信息。该合同将使Majorana合作组织能够开展与拟议的Majorana演示器开发相关的研发活动，Majorana演示器是一种原型Ge探测器阵列，旨在证明未来建造1吨Ge NDBD实验的可行性。这项研究将在两个不同的领域进行：锗探测器的开发和超低背景材料的生产和分析。建立一个NDBD实验的能力，以探测中微子质量的倒层次区域需要一个大的检测器质量的组合NDBD敏感，在1吨的顺序，和前所未有的背景水平，在NDBD信号区域的顺序或小于1计数每年。他们计划部署和评估两种不同的Ge探测器技术，一种基于P型材料，另一种基于N型材料。许多被考虑用于DUSEL的初始实验套件将直接受益于具有极少量U和Th的超净材料的可用性。为了保证材料的纯度，需要在亚微Bq/kg水平上的灵敏度。提高灵敏度的电感耦合等离子体质谱的发展将有利于广泛的应用和未来的实验。Ge探测器的发展将有利于需要非常低的能量阈值的应用，同时还可以减少相关探测器组件的背景。