Collaborative Research: The DarkSide Dark-Matter Search Using Liquid Argon

合作研究：使用液氩进行暗物质搜索

• 批准号: 2310049
• 负责人: Andrew Renshaw
• 金额: $ 67.78万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310049&HistoricalAwards=false
• 关键词: Collaborative; Research; DarkSide; Dark; Matter

A large body of astronomical observations, including galactic rotation curves, strong gravitational lensing, and the anisotropy of the cosmic microwave background, indicates that known matter only accounts for a small fraction of the observed mass-energy of the Universe. A strong candidate for the remaining mass is weakly interacting Dark Matter particles with properties different from ordinary matter. Direct (non-gravitational) detection of dark matter would be a transformational discovery and would represent a watershed moment in the history of science, opening the gates to the investigation of the dark universe. The goal of this award is the testing, on-site installation, commissioning, and transitioning to operations of DarkSide-20k (DS-20k), an experiment capable of pushing the sensitivity of direct dark matter searches beyond that of any current or presently funded experiment. Broader scientific and technological impacts from the project include, among others: the production of low-radioactivity underground argon (UAr) for DS-20k and for nuclear test ban verification and radiometric dating; the continued study of the underground gas source discovered during the UAr exploration, a source which supplies 15 % of the current U.S. helium consumption; and the continued development of 3Dπ, a LAr-based TOF-PET system that can enhance cancer screening while lowering radiation dose.A leading dark matter candidate is a weakly interacting massive particle, or WIMP, a thermal relic of the Big Bang that has a sub-electroweak-scale self-annihilation cross section and a mass in the GeV/c2 to TeV/c2 range. The motion of galactic halo WIMPs relative to a detector on Earth could result in WIMP-nucleus elastic collisions detectable by a low-background, low-energy-threshold detector capable of unambiguously identifying a small number of nuclear recoils from WIMP collisions over the course of a very large exposure. Thanks to its excellent ionization response and unique scintillation light emission characteristics, liquid argon can provide outstanding sensitivity for WIMP-nuclear collisions and strong background suppression. The U.S. NSF groups involved in this program have led the conception and development of the DarkSide-20k liquid argon dark matter search. With support from a separate Mid-scale award, they are responsible for the construction and delivery of the most critical DS-20k components: the liquid argon time projection chamber (LAr TPC) that serves as the heart of the DS-20k dark matter detector along with its critical ancillary components, including the high-voltage delivery system, and the associated cryogenic, purification, and calibration systems. The U.S. NSF groups are also leading the activities for the procurement of the required ultra-low radioactivity argon, which is extracted from a special underground source in Colorado, with support from other US and international funding agencies (U.S. Department of Energy, Istituto Nazionale di Fisica Nucleare of Italy, and Canada Foundation for Innovation). This award will support the U.S. groups for the final testing, on-site installation, commissioning, and transition to operations of the DS-20k detector and preparation for science analyses. The DarkSide-20k experiment will utilize a two-phase time projection chamber with a 50-tonne fill (20-tonne fiducial) to extend the exploration for dark matter, reaching, in a 10 years run, a cross section of 4.9×10−48 cm2 for a 90 % C.L. exclusion and 1.6×10−47 cm2 at a 5 σ discovery significance for a 1 TeV/c2 WIMP, well beyond any current or presently funded experiment. This will lead to either discovery, confirmation, or exclusion of the WIMP dark matter hypothesis down to the level where coherent scatters from atmospheric neutrinos become an unavoidable background. DarkSide-20k will also be sensitive to a galactic supernova neutrino burst originating anywhere in the Milky Way Galaxy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

大量的天文观测，包括银河旋转曲线，强烈的重力镜头和宇宙微波背景的各向异性，表明已知问题仅占宇宙观察到的质量能量的一小部分。剩余质量的有力候选者是弱相互作用的暗物质颗粒，其特性与普通物质不同。对暗物质的直接（非重力）检测将是一个变革性的发现，它将代表科学史上的流域时刻，为黑暗宇宙的投资打开大门。该奖项的目的是测试，现场安装，调试和过渡到Darkside-20k（DS-20K）的操作，该实验能够推动直接暗物质搜索的灵敏度超出任何当前或目前资助的实验的敏感性。该项目的更广泛的科学和技术影响包括：用于DS-20K的基础氩基础（UAR）的低放射性作用以及用于核试验禁令验证和放射测年的产生；对UAR勘探期间发现的潜在气体源的持续研究，该探索源是当前美国氦气消费量的15％的来源； 3Dπ的持续开发是一种基于LAR的TOF-PET系统，可以在降低辐射剂量的同时增强癌症筛查。领先的暗物质候选者是一个弱相互作用的巨大粒子，或者是大爆炸的热液体，具有大爆炸的热液体，具有子电子尺度尺度尺度的自称为GEV/C2至TEV/C2范围内的subs-electrowak-Scale自称横截面。银河光环wimps相对于地球上的检测器的运动可能会导致WIMP-NUCLEUS弹性碰撞通过低空能的低能阈值检测器可检测到的弹性碰撞，能够在很大的暴露过程中明确地识别出少量的WIMP碰撞中的少量核后坐力。感谢其出色的电离响应和独特的闪光灯发射特性，液体氩气可以为WIMP-核碰撞和强烈的背景抑制提供出色的敏感性。参与该计划的美国NSF团体领导了Darkside-20k液体氩气搜索的概念和发展。在单独的中期奖项的支持下，他们负责建造和交付最关键的DS-20K组件：液体氩时间投影室（LAR TPC），它是DS-20K暗物质检测器的核心以及其关键的辅助组件以及其包括高电压输送系统的关键辅助组件，以及相关的低温性，以及相关的低温，纯化，纯化，纯化系统。美国NSF团体还在采购所需的超低放射性氩气领导活动，该活动是从科罗拉多州的特殊地下来源中提取的，并得到了美国其他和国际资助机构的支持（美国伊斯提托托·纳齐奥莱·纳齐奥莱·菲西卡·菲西卡·菲西卡·菲西卡·菲西卡核，意大利核的核，加拿大及加拿大Innovation基金会）。该奖项将支持美国小组进行最终测试，现场安装，调试以及过渡到DS-20K检测器的运营以及进行科学分析的准备。 Darkside-20k实验将利用具有50吨填充（20吨基准）的两相的时间投影室来扩展对暗物质的探索，并在10年的运行中达到了90％C.L.的横截面为4.9×10-48 cm2。排除在1 TEV/C2 WIMP的5σ发现意义下的1.6×10-47 cm2，远远超出了任何当前或提出的资助实验。这将导致发现，确认或排除WIMP暗物质假设，以至于从大气神经元中相干散射成为不可避免的背景的水平。 Darkside-20k也将对以银河系为单位的银河系超新星神经元爆发敏感。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子和更广泛的影响评估标准来通过评估来表现出珍贵的支持。