Collaborative Research: R & D Toward DarkSide-G2, a Second-Generation Direct Search for Dark Matter

合作研究：R

• 批准号: 1242545
• 负责人: Hanguo Wang
• 金额: $ 15.3万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1242545&HistoricalAwards=false
• 关键词: Collaborative; Research; & Toward; DarkSide

The existence of dark matter is known from gravitational effects, but its nature remains a deep mystery. One possibility motivated by other considerations in elementary particle physics is that dark matter consists of undiscovered elementary particles; Weakly Interacting Massive Particles (WIMPs) are one possibility. Evidence for WIMPs that could constitute dark matter may come from experiments at the Large Hadron Collider at CERN or from sensitive astronomical instruments that detect radiation produced by WIMP-WIMP annihilations in galaxy halos. The orbital motion of the WIMPs composing the dark matter halo pervading the galaxy should result in WIMP-nuclear collisions of sufficient energy to be observable by sensitive laboratory apparatus. This award will provide funding for research and development steps to support DarkSide-G2, a second-generation ("G2") direct WIMP search using a liquid argon Time Projection Chamber (TPC) with an active mass of 3.3 tons. Liquid argon is a promising medium for WIMP detection due to its efficient conversion of energy from WIMP-induced nuclear recoils into both ionization and scintillation. The argon scintillation time profile ("pulse shape") depends on the type of ionizing particle, providing particle discrimination that can be used to suppress background. This is one of the most powerful background rejection factors among all dark matter detectors, and when combined with the measurement of ionization, background rejection is even further enhanced. The performance of a ton-scale or larger liquid argon TPC would be limited by the high rate of 39-Ar beta decays if atmospheric argon was used. DarkSide-G2 will use argon collected from underground sources which has been shown to have 39-Ar content lower than atmospheric argon by at least a factor of 150. These funds will allow the groups to carry out the detailed mechanical design work necessary to ensure the functionality of the detector, develop necessary high voltage and data acquisition elements, and develop and identify the extremely radiopure detector components and techniques necessary to maximize the sensitivity of the experiment.Broader impacts: This activity will advance the development of astroparticle physics and its scientific and educational mission in a variety of ways: (1) it will offer a continuing opportunity for the training of students, who will have a chance to contribute a cutting-edge project in fundamental science and advanced engineering; (2) it will benefit society by developing techniques that could find application in areas ranging from national security to medical imaging; and (3) it will support continued development of successful E&O programs such as the LNGS-South Dakota-Princeton summer school for high school students.

暗物质的存在是从引力效应中知道的，但其性质仍然是一个深厚的谜。基本粒子物理学中其他考虑因素的一种可能性是暗物质由未发现的基本颗粒组成。弱相互作用的大颗粒（WIMP）是一种可能性。可能构成暗物质的wimps的证据可能来自CERN的大型强子对撞机的实验，或者来自检测到星系halos中WIMP-WIMP歼灭产生的辐射的敏感天文仪器。组成暗物质光环的轨道运动遍布银河系，应导致敏感的实验室设备可观察到足够能量的wimp-核碰撞。该奖项将为支持Darkside-G2的研发步骤提供资金，该奖项是使用液体氩时时间投影室（TPC）的第二代（“ G2”）直接搜索，其主动质量为3.3吨。液体氩气是WIMP检测的一种有希望的媒介，因为它从WIMP诱导的核后坐力将能量有效地转化为电离和闪烁。氩闪烁时间曲线（“脉冲形状”）取决于电离粒子的类型，提供可用于抑制背景的粒子歧视。这是所有暗物质探测器中最强大的背景排斥因子之一，当与电离的测量结合在一起时，背景排斥将进一步增强。如果使用大气氩气，则量表或较大的液体氩TPC的性能将受到39-ARβ衰变的限制。 Darkside-G2将使用从地下来源收集的氩气，该氩气的内容比至少150倍低于大气氩的39-AR内容。这些资金将使小组能够进行详细的机械设计工作，以确保探测器的功能，确保必要的高电压和数据采集元素，并确定必要的构造元素，并确定极端的放射性探测器探测器，并确定非常放射器的探测器，并确定了极端的无线电图探测器，并确定了无线电图探测器的量实验的影响：这项活动将以各种方式推进Astroparticle物理学及其科学和教育任务的发展：（1）它将为培训学生提供一个持续的机会，他们将有机会在基础科学和高级工程中贡献一个尖端的项目； （2）它将通过开发可以在国家安全到医学成像的领域中找到应用的技术来使社会受益； （3）它将支持持续开发成功的E＆O计划，例如LNGS-South Dakota-Princeton高中生暑期学校。