Liquid-noble Bubble Chambers for Dark Matter and CEvNS Detection

用于暗物质和 CEvNS 检测的液态惰性气泡室

• 批准号: 2310112
• 负责人: Carl Dahl
• 金额: $ 54.99万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard 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=2310112&HistoricalAwards=false
• 关键词: Liquid; noble; Bubble; Chambers; Dark

The identity of dark matter, which makes up nearly 85% of the matter in the Universe, and the origin of the matter/anti-matter asymmetry are two of the current fundamental unknowns in modern physics. Novel instrumentation is under development aimed at resolving both challenges via searches for GeV-scale dark matter and precision measurements of neutrino properties via coherent elastic scattering (CEvNS) of reactor neutrinos. Scalable background-discriminating techniques, like Scintillating Bubble Chambers (SBC), hold the potential to revolutionize the sensitivity in these searches. This award supports personnel at Northwestern University and Northeastern Illinois University in operating, and analyzing the data from, a 10kg liquid-argon SBC located at the Fermi National Accelerator Laboratory located near Batavia IL USA. The team will characterize response of the SBC to determine the low-threshold reach of this technology to distinguish electron and nuclear recoils below approximately 1 keV. The award provides unique opportunities for hands-on instrumentation experiences for undergraduate researchers, with a directed effort to broaden access to, and participation within, the physics community for local low-income and first-generation students. Nuclear recoils in liquid-noble gas bubble chambers simultaneously create a flash of scintillation light and nucleate a single bubble in a superheated liquid target. By combining the electron-recoil insensitivity of the instrument and the position reconstruction of a bubble chamber with the event-by-event energy resolution of a scintillator, the SBC technique holds the potential to eliminate all known backgrounds to dark matter and CEvNS signals. In addition, superheated noble liquids maintain electron-recoil insensitivity at far higher degrees of superheat than can be achieved in existing molecular-fluid bubble chamber, potentially extending the quasi-background-free operation of the SBC to thresholds as low as 100 eV. The SBC ability to discriminate the electron- and nuclear-recoils at low-energy may suppress background event levels to that needed to reach the solar neutrino coherent scattering flow in a dark matter search, and to achieve signal-to-noise of better than 1 in reactor CEvNS studies.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.

暗物质构成了宇宙中近 85% 的物质，其身份和物质/反物质不对称性的起源是现代物理学当前的两个基本未知数。新型仪器正在开发中，旨在解决通过搜索GeV级暗物质和通过反应堆中微子相干弹性散射（CEvNS）精确测量中微子特性的挑战。可扩展的背景辨别技术，例如闪烁气泡室（SBC），有可能彻底改变这些搜索的灵敏度。 该奖项支持西北大学和东北伊利诺伊大学的人员操作位于美国伊利诺伊州巴达维亚附近费米国家加速器实验室的 10 公斤液氩 SBC 并分析其数据。 该团队将表征 SBC 的响应，以确定该技术的低阈值范围，以区分低于约 1 keV 的电子和核反冲。该奖项为本科研究人员提供了亲身实践仪器体验的独特机会，旨在扩大当地低收入和第一代学生接触和参与物理社区的机会。液体-惰性气体气泡室中的核反冲同时产生闪烁光并使过热液体目标中的单个气泡成核。 通过将仪器的电子反冲不敏感性和气泡室的位置重建与闪烁体的逐事件能量分辨率相结合，SBC 技术有可能消除暗物质和 CEvNS 信号的所有已知背景。 此外，过热惰性液体在比现有分子流体气泡室高得多的过热度下保持电子反冲不敏感性，有可能将 SBC 的准无背景操作扩展到低至 100 eV 的阈值。 SBC 区分低能电子和核反冲的能力可以将背景事件水平抑制到暗物质搜索中达到太阳中微子相干散射流所需的水平，并实现优于 1 的信噪比该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。