The XENON1T Dark Matter Project: A Project Proposal from the US Institutions of the XENON Collaboration

XENON1T 暗物质项目：美国 XENON 合作机构的项目提案

• 批准号: 1209979
• 负责人: Elena Aprile
• 金额: $ 721.21万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1209979&HistoricalAwards=false
• 关键词: XENON1T; Dark; Matter; Project; Proposal

This research project addresses the question of the nature of galactic dark matter with a search for Weakly Interacting Massive Particles (WIMPs), using two-phase liquid xenon (LXe) Time Projection Chambers (LXeTPCs) as part of the XENON phased program. XENON100, building upon the success of the XENON10 prototype, represents the current state-of-the-art in WIMP search detectors. With a realistic discovery potential, XENON100 has already reached a world-leading sensitivity, and continues to accrue data at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy towards its ultimate sensitivity reach. To fully probe a particularly favorable region of electroweak physics for WIMP dark matter in search of a first robust and statistically significant discovery, the next phase of the XENON program will be a detector at the ton scale - XENON1T. The worldwide race towards direct dark matter detection has been dramatically accelerated by the remarkable progress and evolution of LXeTPCs. They have shifted the scale of target mass from a few to tens of kilograms whilst simultaneously reducing both electronic and nuclear recoil backgrounds to extremely low levels. The XENON collaboration has demonstrated the effective scaling of LXeTPCs with phased detectors of increasing sensitivity of at least an order of magnitude, and is ready to move to the ton scale. This award will provide funding to the US groups for the construction of the XENON1T detector, cryogenics infrastructure and calibration systems. This experiment is based on a TPC with 2.2 ton of LXe viewed by low radioactivity photomultiplier tubes. By exploiting the excellent self-shielding and 3D position resolution of a LXeTPC, by selecting existing low radioactivity detector materials and by placing the detector in a large active water shield and Cherenkov muon veto, the overall event rate within the fiducial target of 1.1 ton is estimated to be over a factor of 100 lower than the background measured in XENON100. This rate translates to less than one event per ton per year in the WIMP search region - an unprecedented low background level for a dark matter experiment.Broader Impact: The XENON scientific goal to detect the missing mass in the Universe has all the ingredients to captivate the interests and imagination of students and the general public alike. The technological advances of this project can impact society in a number of ways: liquid xenon imaging detectors and related technologies find applications in several fields outside particle astrophysics, including homeland security and medical imaging research.

这个研究项目通过寻找弱相互作用大质量粒子（wimp）来解决银河系暗物质的本质问题，使用两相液态氙（LXe）时间投影室（lxetpc）作为xenon阶段计划的一部分。XENON100以XENON10原型机的成功为基础，代表了当前WIMP搜索探测器的最先进水平。由于具有现实的发现潜力，XENON100已经达到了世界领先的灵敏度，并且在意大利的国家实验室（LNGS）继续积累数据，以达到其最终的灵敏度。为了全面探测WIMP暗物质的一个特别有利的电弱物理区域，以寻找第一个强大的、具有统计学意义的发现，XENON项目的下一阶段将是吨级探测器——XENON1T。lxetpc的显著进步和演变极大地加速了世界范围内直接探测暗物质的竞赛。他们已经将目标质量的尺度从几公斤转移到几十公斤，同时将电子和核后坐力背景降低到极低的水平。XENON合作已经证明了lxetpc的有效缩放，相位检测器的灵敏度至少提高了一个数量级，并且准备转移到吨级规模。该合同将为美国团队提供资金，用于XENON1T探测器、低温基础设施和校准系统的建设。这个实验是基于一个含有2.2吨LXe的TPC，用低放射性光电倍增管观察。通过利用LXeTPC优异的自屏蔽和三维位置分辨率，选择现有的低放射性探测器材料，并将探测器放置在大型活性水屏蔽层和切伦科夫介子中，估计1.1吨基准目标内的总体事件率比XENON100测量的背景低100倍以上。这个速度意味着在WIMP搜索区域每年每吨不到一个事件——对于暗物质实验来说，这是前所未有的低背景水平。更广泛的影响：XENON的科学目标是探测宇宙中缺失的质量，它具有吸引学生和公众的兴趣和想象力的所有成分。该项目的技术进步可以在许多方面影响社会：液态氙成像探测器和相关技术在粒子天体物理学以外的几个领域得到应用，包括国土安全和医学成像研究。