Collaborative Research: MRI-R2 Instrument Development of the Askaryan Radio Array, A Large-scale Radio Cherenkov Neutrino Detector at the South Pole

合作研究： 南极大型射电切伦科夫中微子探测器 Askaryan 射电阵列的 MRI-R2 仪器开发

• 批准号: 1002485
• 负责人: Albrecht Karle
• 金额: $ 131.79万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1002485&HistoricalAwards=false
• 关键词: Collaborative; Research; MRI; R2; Instrument

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). One of the most outstanding questions in astronomy and astrophysics addresses the origin and evolution of the cosmic accelerators that produce the highest energy (UHE) cosmic rays. This question may be best addressed through the observation of UHE cosmogenic neutrinos that travel from their source undeflected by galactic and interstellar magnetic fields and unimpeded by interactions with the cosmic microwave background (CMB) radiation. However, uncertainties in the predicted cosmogenic neutrino fluxes make it difficult to design an array with sufficient sensitivity to collect a statistically meaningful sample of events. At very high energies (above 10^15 eV), neutrinos could be most efficiently detected in dense, radio frequency (RF) transparent media via the Askaryan effect. The abundant cold ice covering the Antarctic, with its exceptional RF clarity, has been hosting several pioneering efforts to develop this RF approach. From the expertise gained in these experiments and utilizing the infrastructure developed by the U.S. Antarctic Program, it is proposed to develop radio-listening equipment that can constitute the Askaryan Radio Array (ARA) and install it in the ice near the geographical South Pole. The primary goal of the ARA array will be establishing the absolute cosmogenic neutrino flux through the modest number of events. As the proposed radio antennae are deployed in ice holes extending below the firn layer to 200-m depth, they will have the ability to distinguish surface noise from sources originating deep in the ice cap (otherwise not possible in balloon-borne experiments). The ARA will have sufficient sensitivity to establish the presence or absence of the secondary UHE neutrinos produced by the interaction of cosmic rays with CMB. Such an observatory would also provide a unique probe of long-baseline high-energy neutrino interactions unattainable with any manmade neutrino beam. The adopted clustered geometry of the array (in which a single localized cluster may act as a standalone array) would allow trading the precise angular resolution for the increased event rates. The flux measurement and experience gained in operating the limited number of stations would frame the performance requirements needed to expand the array in the future to measure a larger number of neutrinos with greater angular precision in order to study their spectrum and origins. The project will continue contributing significantly to the training of the next generation of scientists by integrating graduate and undergraduate education with the technology and instrumentation development.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。天文学和天体物理学中最突出的问题之一是产生最高能量（UHE）宇宙射线的宇宙加速器的起源和演化。这个问题可以通过UHE宇宙成因中微子的观测得到最好的解决，这些中微子从其来源出发，不受银河和星际磁场的偏转，也不受宇宙微波背景辐射（CMB）的相互作用的阻碍。然而，预测宇宙成因中微子通量的不确定性使得很难设计出具有足够灵敏度的阵列来收集有统计意义的事件样本。在非常高的能量（10^15 eV以上）下，中微子可以通过阿斯卡里安效应在致密的射频（RF）透明介质中最有效地检测到。覆盖南极的丰富的冷冰，以其特殊的RF清晰度，一直在主持开发这种RF方法的几项开创性工作。从这些实验中获得的专业知识和利用美国南极计划开发的基础设施，建议开发无线电收听设备，可以组成Askaryan无线电阵列（ARA）并将其安装在地理南极附近的冰层中。ARA阵列的主要目标将是通过适度数量的事件来确定绝对的宇宙成因中微子通量。由于拟议的无线电天线部署在冰洞中，冰洞延伸到积雪层以下200米深，它们将有能力区分表面噪音和冰帽深处的来源（否则在气球实验中是不可能的）。ARA将有足够的灵敏度来确定宇宙射线与CMB相互作用产生的次级UHE中微子的存在或不存在。这样一个天文台还将提供一个独特的探测长基线高能中微子相互作用，这是任何人造中微子束都无法实现的。所采用的阵列的集群几何结构（其中单个局部集群可以充当独立阵列）将允许以精确的角分辨率换取增加的事件率。通量测量和在操作数量有限的台站中获得的经验将确定未来扩大阵列所需的性能要求，以便以更高的角度精度测量更多的中微子，从而研究它们的光谱和起源。该项目将通过将研究生和本科生教育与技术和仪器开发相结合，继续为培养下一代科学家做出重大贡献。