Low-Temperature Scintillation for Rare-Event Searches

对于罕见事件，比如可能构成宇宙中大部分物质的暗物质粒子的相互作用，科学家们很难在放射性背景的干草堆中识别出微小的信号。背景抑制探测器技术的改进推动了进展。一种适用于许多靶核的有前途的技术是在低温下测量闪烁和声子。为了开发这样的探测器，我们已经建立了一个独特的有效的测试床，以测量闪烁低至4 K。我们将研究纯的和掺杂的碘化钠，与原型的背景拒绝闪烁声子探测器的目标。例如，在SNOLAB未来的实验中部署，他们可以验证长期存在但有争议的DAMA暗物质声明，该声明基于仅限反褶曲的设备。我们还将研究其他无机闪烁体，如CsI和ZnWO 4，它们可能用于暗物质搜索，如CRESST，以及像ZnMoO 4这样的双β衰变材料。此外，我们将探讨贵金属液体探测器中使用的各种材料的闪烁特性，这些材料可能会影响它们使用脉冲形状鉴别拒绝背景的能力。这将对DEAP等实验感兴趣。我们将研究的另一类材料是液体有机溶剂，如线性烷基苯，在室温下众所周知，但在低温下没有研究。最后，我们将研究骨折作为一个背景在recruitors。为此，我们将在低温下进行一项实验，以测量制冷机中裂缝发出的光。这些结果可能对理解CRESST暗物质搜索最近有趣的结果有影响。与法国一个材料小组就这一主题进行交流的资金已从法国-加拿大研究基金获得。总体而言，该计划将培养2名博士后，5名研究生和5名本科生的前沿实验技能和数据分析。

Searches for rare-events, like interactions of the dark matter particles that may make up the bulk of the matter in the Universe, struggle to identify small signals in a haystack of radioactive background. Progress has been driven by improvements in background-rejecting detector technology. One promising technology applicable to many target nuclei is the measurement of scintillation and phonons at cryogenic temperatures. To develop such detectors, we have set up a uniquely efficient test bed to measure scintillation down to 4 K. We will study pure and doped NaI, with the goal of prototyping background-rejecting scintillation-phonon detectors. Deployed in a future experiment at SNOLAB for instance, they could verify the longstanding but controversial DAMA dark matter claim based on scintillation-only devices. We will also investigate other inorganic scintillators like CsI and ZnWO4 that may be of use in dark matter searches such as CRESST, as well as materials like ZnMoO4 of interest for double beta decay. In addition, we will explore the scintillation properties of various materials used in noble liquid detectors that could affect their ability to reject background using pulse-shape discrimination. This will be of interest to experiments like DEAP. A different class of materials we will investigate are liquid organic scintillators like linear-alkyl-benzene, well-known at room temperature, but not studied at low temperatures. Lastly, we will examine fractures as a background in scintillators. For this, we will pursue to low temperatures an experiment to measure the light emitted by fractures in scintillators. The results could have implications for understanding the recent intriguing results of the CRESST dark matter search. Funding for exchanges with a materials group in France on this topic has been obtained from the France-Canada Research Fund. Overall, this program will train 2 postdocs, 5 graduate students, and 5 undergraduates in leading-edge experimental skills and data analysis.