Development of noble gas/liquid detectors for neutrinoless double beta decay and dark matter searches

当今物理学中一些最引人注目的问题，如发现暗物质粒子或通过无中微子双β衰变来确定中微子质量尺度，只能通过对每年数十次事件级的罕见过程敏感的大质量、低本底探测器来回答。这些探测器必须由超纯材料建造，以最大限度地减少内部产生的背景，与实验环境的局部背景适当屏蔽，并位于地下深处，以尽量减少宇宙射线诱导背景的污染。Efforts目前正在开发利用电离诱导电荷和/或闪烁光作为探测机制的稀有气体/液体探测器。作为此类探测器的中心目标，通常是液态或气态的Ar或Xe，可以很容易地提纯，将大多数背景降低到十亿分之几的水平。探测器信号可以提供良好的能量分辨率和位置重建，从而能够显著抑制背景水平和有效识别信号事件。*拟议的研究将专注于稀有气体/液体探测器技术的发展，目标是设计和建造用于暗物质粒子和无中微子双β衰变搜索的大规模探测器。*卡尔顿大学正在开发具有闪烁光读数的大型气体氙气时间投影室(TPC)，并与强化的氙气天文台(EXO)合作。测量136Xe的双β衰变谱，寻找无中微子的双β衰变信号。用于暗物质研究的液态Ar闪烁探测器的开发将与使用Ar脉冲形状(DEAP)的暗物质实验一起进行。SNOLAB设施提供6000米水当量的宇宙射线屏蔽，是举办这两项实验的理想地点。

Some of the most compelling questions in present-day physics, such as discovering dark matter particles ordetermining the neutrino mass scale via neutrinoless double beta decay, can only be answered via large-mass, low-background detectors sensitive to rare processes at the level of tens of events/year.  Such detectors must be constructed from ultra-pure materials to minimize internally generated backgrounds, properly shielded from backgrounds local to the experimental environment, and located deep underground to minimize contamination from cosmic-ray induced backgrounds.Efforts are currently underway to develop noble gas/liquid detectors utilizing ionization induced charge and/or scintillation light as the detection mechanism.  The central target for such detectors, typically Argon or Xenon in liquid or gaseous form, can be readily purified to reduce most backgrounds to the parts per billion level.  The detector signals can provide good energy resolution and position reconstruction enabling significant suppression of background levels and efficient identification of signal events.  The proposed research will focus on the development of noble gas/liquid detector technology with the  aim of designing and constructing large-scale detectors for dark matter particle and neutrinoless double beta decay searches.  A large-scale gaseous Xenon time projection chamber (TPC) with scintillation light readout is being developed at Carleton with the Enriched Xenon Observatory (EXO) collaboration.  The goal here is to measure the double beta decay spectrum of 136Xe and search for a neutrinoless double beta decay signal. Development of a liquid argon scintillation detector for a dark matter search will be carried out in conjunction with the Dark Matter Experiment using Argon Pulse shapes (DEAP). The SNOLAB facility, providing 6000 meters water equivalent of cosmic-ray shielding, is the ideal site to host both of these experiments.