Collaborative Research: Maximizing Background Rejection in SuperCDMS Dark Matter Detectors

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。暗物质的性质是当今物理学中最重要的研究课题之一。它涉及粒子物理学、天体物理学和宇宙学中尚未回答的基本问题。暗物质的一个可能候选者是弱相互作用大质量粒子（WIMP）。低温暗物质搜索（CDMS）实验的目标是开发一种探测器，如果存在这种WIMP，它具有观察这种WIMP的灵敏度。该项目的研究目标是通过显着改善能量、位置和定时确定来改善当前和未来SuperCDMS探测器的背景抑制。这项工作将通过以下任务对目前在苏丹进行的超级CDMS实验以及该合作的下一代5公斤探测器的设计和成功运行作出重要贡献，该探测器将用于未来的100公斤实验及更大的实验：PI将模拟声子脉冲的时间结构作为位置，能量和反冲类型的函数，以了解其当前模型和数据之间的差异的来源;和ii）开发一种新型的检测器表征和校准设施，以测量声子脉冲形状和电离响应作为事件能量，位置和反冲类型的函数。探测器响应的这种独特映射将用于改进上述探测器模拟，并提供用于定义背景抑制分析的详尽的经验数据集。该计划的更广泛的影响包括培养实验物理学的研究生和博士后研究人员。所开发的技术和方法可直接应用于中微子和X射线天体物理学，并可广泛应用于超导探测器，用于材料科学和核同位素鉴定。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The nature of dark matter is one of the most important research topics in physics today. It pertains to fundamental unanswered questions in particle physics, astrophysics, and cosmology. A possible candidate for dark matter is a Weakly Interacting Massive Particle (WIMP). The goal of the Cryogenic Dark matter Search (CDMS) experiment is to develop a detector that has the sensitivity to observe such WIMPs if they exist. The research objective of this project is to improve the background rejection of current and future SuperCDMS detectors by means of significantly improved energy, position, and timing determination. This work will make important contributions to both the current SuperCDMS experiment at Soudan and the design and successful operation of the collaboration's next-generation, 5 kg detectors for a future 100 kg experiment and beyond through the following tasks: i) Development of SuperCDMS detector models from first principles. The PI will model the time structure of the phonon pulses as a function of position, energy, and recoil type to understand the source of discrepancies between their current models and data; and ii) Development of a novel detector characterization and calibration facility to measure phonon pulse shapes and ionization response as a function of event energy, position, and recoil type. This unique mapping of detector response will be used to refine the detector simulation described above as well as provide an exhaustive, empirical data set for defining the background rejection analyses. The broader impact of the program includes training graduate students and postdoctoral researchers in experimental physics. The technology and methods developed have direct applications in neutrino and X-ray astrophysics as well as broader applications in superconducting detectors with uses in material science and nuclear isotope identification.