DUSEL R&D for Measuring External Sources of Background (R&D) at Homestake for Double Beta Decay and Dark Matter Experiments

未来的DUSEL实验将需要了解放射性的外部来源，包括在DUSEL场地不同水平的介子诱导中子。这些外部背景，特别是快中子和介子诱导过程产生的宇宙放射性，必须在地下实验中消除，以追求双β衰变，寻找暗物质候选者，以及低能中微子的振荡。该奖项将提供资金，用液体闪烁体、碘化钠和锗探测器来测量这种背景。这些测量的结果将使实验能够根据其设计的灵敏度和屏蔽要求被放置在不同的水平上。在300英尺水平上测量介子诱导的中子通量将使人们能够对所有传入的实验进行蒙特卡罗模拟代码的基准测试。测量和理解无中微子双β衰变实验中屏蔽和探测材料的高能中子激发对于解释结果和建立屏蔽要求至关重要。另一方面，测量部分伽马射线截面为蒙特卡罗模拟基准提供了有用的数据。这些资金将提供分析现有数据集和获取更多数据所需的支持。在更广泛的影响中，值得注意的是，描述DUSEL地点也有助于其他DUSEL实验，如地下核天体物理加速器计划和质子衰变实验。从建议的测量中获得的知识可以有广泛的应用。拟议的研究活动涉及来自两个州两个机构的两名本科生，对教育和推广产生了影响。

Future DUSEL experiments will need to know the external sources of radioactivity including muon-induced neutrons at different levels of the DUSEL site. These external backgrounds, particularly fast neutrons and cosmogenic radioactivity from muon-induced processes, must be eliminated for underground experiments in pursuit of double beta decay, searches for dark matter candidates, and oscillations of low-energy neutrinos. This award will provide funds to measure such backgrounds with liquid scintillator, sodium iodide and germanium detectors. The results from such measurements will enable the experiments to be placed at different levels according to their designed sensitivity and shielding requirements. Measuring muon-induced neutron flux at the 300-ft level will enable one to benchmark Monte Carlo simulation codes for all incoming experiments. Measuring and understanding high energy neutron excitation of the shielding and detector materials for neutrinoless double-beta decay experiments are crucial for interpreting results and establishing shielding requirements. On the other hand, measuring partial gamma-ray cross sections provides useful data for benchmarking Monte Carlo simulation. These funds will provide the support needed to analyze existing data sets and to take more data.Among the broader impacts, it is noted that characterizing the DUSEL site is also useful to other DUSEL experiments, such as the underground nuclear astrophysics accelerator program and proton decay experiments. Knowledge gained from the proposed measurements can have wide-ranging application. The proposed research activities have impact on education and outreach by involving two undergraduate students from two institutions in two states.