Dusel R&D: A Multiplicity Meter for Benchmarking Cosmogenic Neutron Backgrounds for Underground Experiments

杜塞尔R

• 批准号: 0705055
• 负责人: Daniel Akerib
• 金额: $ 45万
• 依托单位: Case Western Reserve University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0705055&HistoricalAwards=false
• 关键词: Dusel; R& Multiplicity; Meter; Benchmarking

The nature of dark matter is one of the most important outstanding issues in particle physics, cosmology and astrophysics. A leading hypothesis is that Weakly Interacting Massive Particles, or WIMPs, were produced in the early universe and make up the dark matter. So far this matter has only been observed through its gravitational effects. WIMPs cannot be Standard Model particles and so their discovery would hail a new form of matter. A detection would also help solve a long-standing riddle in cosmology that even questions our understanding of gravity. Dark matter is concentrated in the halos of galaxies, including the Milky Way. If WIMPs make up these halos they can be detected via scattering from atomic nuclei in an underground detector.Nuclear recoils from fast neutrons in underground laboratories are one of the most challenging backgrounds to WIMP detection. The rate of this background is at present poorly quantified. In this proposal, funds are requested for a portable experiment that will pin down their rate to about 10% by operating it in the Soudan Mine for a period of at least one year at a depth of 2000 meters of water equivalent. The long-used technique of gadolinium-loaded liquid scintillator will be employed to implement a neutron multiplicity meter adjacent to a lead radiator," similar to the shielding in an actual dark matter experiment. All dark matter experiments, as well as many other underground experiments, rely on knowledge of the neutron background environment. Being able to predict this background with greater reliability will serve well this community, and provide improved extrapolations for experiments aiming to operate in deeper sites in the future.

暗物质的性质是粒子物理学、宇宙学和天体物理学中最重要的悬而未决的问题之一。一个主要的假设是，弱相互作用大质量粒子（WIMP）是在早期宇宙中产生的，并构成了暗物质。到目前为止，这种物质只能通过它的引力效应来观察。WIMP不可能是标准模型粒子，因此它们的发现将为一种新的物质形式欢呼。探测还将有助于解决宇宙学中一个长期存在的谜团，这个谜团甚至质疑我们对引力的理解。暗物质集中在星系的晕中，包括银河系。 如果WIMP构成了这些晕，那么它们可以通过地下探测器中原子核的散射来探测。地下实验室中快中子的核反冲是WIMP探测最具挑战性的背景之一。目前，这一背景的发生率尚不清楚。在本提案中，要求为便携式实验提供资金，通过在Soudan矿2000米水深当量处运行至少一年，将其速率固定在10%左右。 长期使用的加钆液体闪烁体技术将被用来实现与铅辐射器相邻的中子多重性计，”类似于实际暗物质实验中的屏蔽。所有的暗物质实验，以及许多其他地下实验，都依赖于对中子背景环境的了解。能够以更高的可靠性预测这种背景将很好地服务于这个社区，并为未来在更深的地点进行实验提供改进的推断。