LZ Dark Matter Search

LZ 暗物质搜索

• 批准号: 1506068
• 负责人: Daniel McKinsey
• 金额: $ 12万
• 依托单位: Yale University
• 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: 2015-06-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506068&HistoricalAwards=false
• 关键词: LZ; Dark; Matter; Search

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 is of fundamental importance to cosmology, astrophysics, and high-energy particle physics. A leading hypothesis is that it is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced moments after the Big Bang. If WIMPs are the dark matter, then their presence in our galaxy may be detectable via scattering from atomic nuclei in detectors located deep underground to help reject backgrounds due to cosmic rays. LZ is a ~7-tonne liquid xenon (LXe) dark matter detector to be installed at the 4850-foot level of the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to look for dark matter. This work will contribute to the design of that detector. Development of technology related to LXe will find use in the increasing number of experiments worldwide using noble liquids as detection materials. These projects will also result in technical training in radiation detection, cryogenics, and gas purification for graduate and undergraduate students. LXe has practical applications to gamma ray imaging for astrophysics, Homeland Security, and medical imaging.This detector will use established liquid xenon time projection chamber technology with readout of primary and secondary scintillation signals for particle identification, together with 3-D position reconstruction to exploit the self-shielding of the liquid xenon, removal of surface artifacts, and calibration of position-dependent response functions. The design also features a gadolinium-loaded liquid scintillator veto that will hermetically enclose the central xenon detector and provide powerful tagging of background neutrons and gammas. The LZ experiment will have world-leading sensitivity to WIMP dark matter with a sensitivity about 400 times better than current results and covering a substantial range of theoretically motivated candidates. This award will provide funding to enable this research group to continue to contribute to the LZ dark matter experiment with work on the cathode high voltage delivery system.

多项天文观测证实，宇宙中约 85% 的物质并非由已知粒子组成。破译这种所谓的暗物质的本质对于宇宙学、天体物理学和高能粒子物理学至关重要。一个主要的假设是，它由大爆炸后不久产生的弱相互作用大质量粒子（WIMP）组成。如果 WIMP 是暗物质，那么它们在我们银河系中的存在可以通过位于地下深处的探测器中原子核的散射来探测到，以帮助排除宇宙射线造成的背景。 LZ 是一个约 7 吨的液氙 (LXe) 暗物质探测器，将安装在南达科他州利德市桑福德地下研究设施 (SURF) 4850 英尺高处，用于寻找暗物质。这项工作将有助于该探测器的设计。 LXe 相关技术的发展将在全球范围内越来越多使用惰性液体作为检测材料的实验中得到应用。这些项目还将为研究生和本科生提供辐射探测、低温学和气体净化方面的技术培训。 LXe 在天体物理学、国土安全和医学成像的伽马射线成像中具有实际应用。该探测器将使用成熟的液氙时间投影室技术，读出用于粒子识别的初级和次级闪烁信号，以及 3D 位置重建，以利用液氙的自屏蔽、去除表面伪影以及校准位置相关响应函数。该设计还具有装载钆的液体闪烁体否决器，它将密封地包围中央氙探测器，并提供背景中子和伽马的强大标记。 LZ 实验将对 WIMP 暗物质具有世界领先的灵敏度，其灵敏度比当前结果高出约 400 倍，并涵盖大量具有理论动机的候选者。该奖项将为该研究小组提供资金，使其能够通过阴极高压传输系统的工作继续为 LZ 暗物质实验做出贡献。