DarkSide-20k - URANIA Project

不能用可见物质来解释的引力效应是有据可查的，尽管它们的来源仍然未知。对这些观测结果的一个合理解释是，存在一种尚未被发现的基本弱相互作用大质量粒子（WIMP）。银河晕wimp相对于地球上探测器的运动可能导致wimp -核弹性碰撞，低背景，低阈值探测器能够在非常大的暴露过程中明确识别少量的核反冲。该奖项支持DarkSide-20k （DS-20k）探测器，这是一种液态氩时间投影室，旨在实现对大质量（30 GeV/c2以上）WIMP暗物质的领先灵敏度，为位于CO . Cortez的URANIA工厂提供资金，用于从地下源（UAr）中大量提取低放射性氩气。这些资金将用于由美国国家科学基金会资助的团体直接负责的基础设施。该项目的更广泛的科学影响包括发现了一种新的、商业上可行的氦源，目前占美国产量的15%，并为DS-20k生产了数百吨低放射性UAr。提取设施可以继续生产地下氩气，用于需要氩气来实现其科学目标的其他感兴趣的粒子物理实验，以及用于其他技术用途，包括禁止核试验核查和放射性测年。建造DS-20k将需要及时采购大量的UAr。这将由URANIA完成，这是一个能够每天提取250公斤氩的氩提取和净化工厂。URANIA工厂本身由意大利机构（INFN）提供资金，并将由合同供应商按照URANIA项目团队制定的规范建造。提取设施场地的准备，以及工厂的安装和调试，由nsf支持的小组负责，并由该奖项资助。这些都是项目的关键组成部分，需要美国团体的技术专长。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Gravitational effects that cannot be explained by visible matter are well-documented, though their source remains unknown. A well-motivated explanation for these observations is the existence of an as-yet-undiscovered elementary Weakly Interacting Massive Particle (WIMP). 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-threshold detector capable of unambiguously identifying a small number of nuclear recoils over the course of a very large exposure.This award supports the DarkSide-20k (DS-20k) detector, a liquid argon time projection chamber designed to achieve leading sensitivity to high-mass (above 30 GeV/c2) WIMP dark matter, by providing funding for the URANIA plant, in Cortez, CO, for the high-volume extraction of low-radioactivity argon gas from an underground source (UAr). The funds will be used for pieces of infrastructure that are the direct responsibility of the US NSF-funded groups. Scientific broader impacts of the project include the discovery of a novel, commercially viable helium source that today supplies 15% of the US production and the production of hundreds of tonnes of low-radioactivity UAr for DS-20k. The extraction facility could continue to produce underground argon for other interested particle physics experiments that require UAr to achieve their scientific objectives, as well as for other technical uses including nuclear test ban verification and radiometric dating.Constructing DS-20k will require that large amounts of UAr be procured in timely fashion. This will be accomplished by URANIA, an argon extraction and purification plant capable of extracting 250 kg/day of UAr. The URANIA plant itself is funded by the Italian Agency (INFN) and will be built by a contracted vendor following specifications established by the URANIA Project team. The preparation of the extraction facility site, as well as the installation and commissioning of the plant, falls under the responsibility of the NSF-supported groups and is funded by this award. These are the critical components of the project that require the technical expertise of the U.S. groups.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.