Collaborative Research: Estimating the mantle contribution to the Geo-neutrino flux at the Sudbury Neutrino Observatory

合作研究：估计萨德伯里中微子观测站地幔对地中微子通量的贡献

• 批准号: 1067983
• 负责人: William McDonough
• 金额: $ 26.91万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1067983&HistoricalAwards=false
• 关键词: Collaborative; Research; Estimating; mantle; contribution

The investigators will identify the abundance and distribution of thorium (Th) and uranium (U) in the continental crust and underlying mantle beneath a 1000-km wide area in southern Canada - northern central US where there will be an underground laboratory constructed to measure the flux of geoneutrinos from inside the Earth. Geoneutrinos are electron antineutrinos produced inside the Earth during beta-decays of naturally occurring radioactive elements. These particles are messengers of the abundances and distribution of radioactive elements within our planet, and provide direct information that constrains all geochemical and geophysical models of the planet. Geoneutrino detection was successfully performed by two sub-kiloton, liquid scintillator detectors. The SNO+ detector (Sudbury, Ontario, Canada), a kiloton detector, will be the first liquid scintillation neutrino detector with ample fiducial volume and low enough reactor background to allow detection of sufficient geoneutrino counts in approximately 3 years to constrain the Th and U content of the Earth to within ~±25% (1 sigma) or better. All of these detectors are also capable of detecting the electron antineutrino emissions of power nuclear reactors. By constraining the Earth's nuclear power to uncertainties of about 12% for the regional continental crust the investigators will be able to assess critically the Th and U content of the mantle. Their goals are to test interpretive compositional Earth models against real time neutrino data. The integration of these two independent data sets will provide transformative insights into how the Earth works and constrain the energy source driving Plate Tectonics. In turn, these data will provide unique bulk compositional information about the crust and mantle. The team will unite scientists from earth sciences and physics with shared goals in antineutrino detection research and its applications. Undergraduate and graduate students will be involved in this research. Results will be communicated to the general public, K-12 educators and members of the US intelligence community. The detection of antineutrinos for nuclear nonproliferation purposes is of significant interest to US national security agencies.

研究人员将确定在加拿大南部-美国中部北方1000公里宽的区域下的大陆地壳和下地幔中钍（Th）和铀（U）的丰度和分布，那里将建造一个地下实验室来测量地球内部的地中微子通量。地中微子是在地球内部自然存在的放射性元素的β衰变过程中产生的电子反中微子。这些粒子是地球内放射性元素丰度和分布的信使，并提供直接信息，制约地球的所有地球化学和地球物理模型。地球中微子探测成功地进行了两个次千吨级，液体闪烁体探测器。SNO+探测器（Sudbury，安大略，加拿大），一个千吨级探测器，将是第一个液体闪烁中微子探测器，具有足够的基准体积和足够低的反应堆背景，允许在大约3年内探测足够的地中微子计数，将地球的Th和U含量限制在±25%（1 sigma）或更好。 所有这些探测器也能够探测动力核反应堆的电子反中微子发射。通过限制地球的核功率的不确定性约为12%的区域大陆地壳的研究人员将能够评估严格的钍和铀的地幔含量。他们的目标是用真实的时间中微子数据来测试解释性的地球成分模型。这两个独立数据集的整合将为地球如何运作提供变革性的见解，并限制驱动板块构造的能源。 反过来，这些数据将提供关于地壳和地幔的独特的大量成分信息。该团队将联合来自地球科学和物理学的科学家，在反中微子探测研究及其应用方面实现共同目标。本科生和研究生将参与这项研究。结果将传达给公众，K-12教育工作者和美国情报界成员。为防止核扩散而探测反中微子对美国国家安全机构具有重大意义。