CAREER: R&D for Future Noble-Liquid-Based Dark Matter Searches: Hybrid Photosensors and Intrinsic Background Rejection

职业：R

• 批准号: 1455351
• 负责人: Emilija Pantic
• 金额: $ 69.84万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1455351&HistoricalAwards=false
• 关键词: CAREER; R&D; Future; Noble; Liquid

Multiple astronomical observations have established that about 85% of the matter in the universe is not made of known particles. Deciphering the nature of this so-called Dark Matter (DM) is of fundamental importance to cosmology, astrophysics, and high-energy particle physics. Our knowledge about DM existence has grown significantly over the past decade, mainly through observation of its gravitational influence. However, fundamental questions still remain unsolved: Is DM a particle? Is there more than one type of DM? Does it interact via non-gravitational force? We are systematically searching for DM and scrutinizing the claims of its detection, but to date, no one has reported a conclusive DM signal. This forces us to broaden our search, as well as to develop technologies capable of making measurements orders of magnitude more sensitive than what is currently available. Direct DM detection experiments aim to measure the energy deposited by DM as it scatters off the atoms in a detector. Among them, noble-liquid-based experiments are presently leading the field and are expected to improve the sensitivity of DM searches by two orders of magnitude by the end of this decade. To achieve this, the experiments rely heavily on increasing target mass and achieving a very low background environment. The current generation of noble-liquid DM detectors is limited by the radioactivity in the detector materials, the photomultipliers (PMTs), and the target itself. This award will support the development of radio-pure hybrid photosensors with a simpler internal structure, much lower intrinsic sensor radioactivity, and significantly better charge resolution than a PMT. The UC Davis team will also design and construct a noble liquid test cell that will precisely tailor the effects of detector design parameters on the charge-to-light ratio background rejection. This effort will be combined with a related analysis in the liquid-argon-based DarkSide-50 DM search program. Employing the charge-to-light ratio rejection can extend the sensitivity of the DarkSide-50 detector in the energy region of importance for low mass DM searches.The main focus of the broader impacts is hands-on experience for students, ranging from high school to graduate school, combined with providing mentorship on how to successfully develop a STEM career. The PI will coordinate these efforts with two summer school programs: Nuclear Analytical Techniques (NAT) and the California State Summer School for Mathematics and Science (COSMOS). This award also aims to increase participation in the NAT School of students of underrepresented groups who will be selected through the application process of the Research Experiences for Undergraduates (REU) Physics program at UC Davis.

多项天文观测证实，宇宙中约85%的物质不是由已知粒子组成的。破译这种所谓的暗物质(DM)的本质对于宇宙学、天体物理学和高能粒子物理都是至关重要的。在过去的十年里，我们对DM存在的了解有了显著的增长，主要是通过观察其引力影响。然而，根本的问题仍然没有解决：DM是粒子吗？是否存在不止一种类型的DM？它是通过非引力相互作用的吗？我们正在系统地搜索DM并仔细检查其检测到的说法，但到目前为止，还没有人报告确切的DM信号。这迫使我们扩大搜索范围，并开发能够使测量比目前可用的更灵敏的技术。直接DM检测实验旨在测量DM在探测器中从原子上散射时沉积的能量。其中，基于贵重液体的实验目前处于该领域的领先地位，预计到本十年末将把DM搜索的灵敏度提高两个数量级。为了实现这一点，实验在很大程度上依赖于增加目标质量和实现非常低的背景环境。当前一代稀有液体DM探测器受到探测器材料、光电倍增管(PMT)和靶材本身放射性的限制。该奖项将支持开发具有更简单的内部结构、更低的固有传感器放射性以及比光电倍增管更好的电荷分辨率的无线电-纯混合光电传感器的开发。加州大学戴维斯分校的团队还将设计和建造一种贵重液体测试室，该测试室将精确地定制探测器设计参数对荷光比背景抑制的影响。这项工作将与基于液态Ar的Darkside-50 DM搜索计划中的相关分析相结合。使用荷光比抑制可以在低质量DM搜索的重要能量区域扩展Darkside-50探测器的灵敏度。更广泛影响的主要焦点是为从高中到研究生的学生提供实践体验，并提供如何成功发展STEM职业生涯的指导。国际和平研究所将与两个暑期学校项目协调这些努力：核分析技术(NAT)和加州州立数学与科学暑期学校(COSMOS)。该奖项还旨在通过加州大学戴维斯分校本科生研究体验(REU)物理项目的申请程序，增加未被充分代表的群体的学生对NAT学校的参与。