A Midscale U.S. Proposal for the LEGEND 200 Experiment

美国关于 LEGEND 200 实验的中型提案

• 批准号: 1812374
• 负责人: John Wilkerson
• 金额: $ 754.41万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1812374&HistoricalAwards=false
• 关键词: Midscale; U.S.; Proposal; LEGEND; 200

Neutrinos are the most prolific particle in the Universe and they have an important role in understanding why the Universe has more matter than anti-matter. Neutrinos have very small mass and zero electric charge so they could be their own anti-particle. If that is the case, this might explain why there is more matter than anti-matter. The only experimentally feasible way to answer this question is to look for neutrinoless double beta decay (NLDBD), a very rare form of nuclear decay. This award will support a project that adds to and brings together the best U.S. (Majorana Demonstrator) and European (GERDA) experiments using germanium to look for neutrinoless double beta decay into a new experiment called LEGEND-200. The experiment will use 200 kg of special detectors made out of enriched germanium and will take place at the Laboratori Nazionali del Gran Sasso in Italy. Among the fields that may benefit from the new technology developed as part of the experiment are: environmental monitoring; atmospheric, ocean, and groundwater environmental transport; methods of radioactive dating; reactor monitoring; bioassay for determining very low occupational exposures to radiation; and biological studies involving radiotracers at very low activities. Students and postdocs will be trained in underground science related disciplines, such as low-background techniques, detector technology, nuclear physics and neutrino physics. The current generation Ge-76 experiments, GERDA and the Majorana Demonstrator (MJD), utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the NLDBD signal region compared to other NLDBD experiments. Building on this success, the LEGEND Collaboration is developing a next-generation NLDBD experiment with discovery potential at a half-life of 1028 years. This award provides mid-scale support for U.S. involvement in building and commissioning an almost-next-generation NLDBD experiment using up to 200 kg of Ge-76 diodes ie LEGEND-200 (L-200) that has potential to deliver physics and serve as a forerunner to a future ton-scale experiment. L-200 is based on combining the techniques developed by MJD to produce ultra-clean components and GERDA's background suppression from shielding the detectors in a liquid argon bath, in addition to physically combining the existing MJD and GERDA detectors, resources and infrastructure with new detectors. L-200 will be based at the Laboratori Nazionali del Gran Sasso in Italy, and deploy the detectors in the existing GERDA cryostat. L-200 would have world leading discovery potential and a half-life sensitivity of 10^27 yr for a 1 t*yr exposure.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.

中微子是宇宙中最多产的粒子，它们在理解为什么宇宙中有更多的物质而不是反物质方面发挥着重要作用。中微子具有非常小的质量和零电荷，因此它们可能是自己的反粒子。如果是这样的话，这可能解释了为什么物质比反物质多。要回答这个问题，唯一在实验上可行的方法是寻找无中微子双贝塔衰变(NLDBD)，这是一种非常罕见的核衰变形式。该奖项将支持一个项目，该项目将美国(Majorana Demonator)和欧洲(Gerda)使用锗寻找无中微子双β衰变的最好实验添加到一个名为Legend-200的新实验中，并将其结合在一起。这项实验将使用200公斤由浓缩锗制成的特殊探测器，并将在意大利的实验室纳齐奥利·德尔格兰萨索进行。作为实验的一部分，可能受益于新技术的领域包括：环境监测；大气、海洋和地下水环境运输；放射性测年方法；反应堆监测；确定极低职业辐射暴露的生物测定；以及涉及极低放射性示踪剂的生物学研究。学生和博士后将接受地下科学相关学科的培训，如低背景技术、探测器技术、核物理和中微子物理。与其他NLDBD实验相比，当前一代的GE-76实验Gerda和Majorana Demonator(MJD)利用本征能量分辨率为0.12%的高纯度锗探测器，在NLDBD信号区实现了最低的本底。在这一成功的基础上，传奇合作正在开发具有发现潜力的下一代NLDBD实验，半衰期为1028年。该奖项为美国参与建造和调试几乎是下一代NLDBD实验提供了中等规模的支持，该实验使用了多达200公斤的GE-76二极管，即联想-200(L-200)，该实验具有提供物理学的潜力，并成为未来吨级实验的先行者。L-200的基础是结合了MJD开发的生产超清洁组件的技术和Gerda的背景抑制，使其不会在液氩熔池中屏蔽探测器，此外，还将现有的MJD和Gerda探测器、资源和基础设施与新的探测器实际结合在一起。L-200将驻扎在意大利的实验室纳齐奥利·德尔格兰萨索，并在现有的格尔达低温恒温器中部署探测器。L-200将具有世界领先的发现潜力和1t*年暴露的半衰期灵敏度为10^27年。这一奖项反映了美国国家科学基金会的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Bayesian inference of high-purity germanium detector impurities based on capacitance measurements and machine-learning accelerated capacitance calculations

基于电容测量和机器学习加速电容计算的高纯度锗探测器杂质的贝叶斯推断

• DOI: 10.1140/epjc/s10052-023-11509-8
• 发表时间: 2023
• 期刊: The European Physical Journal C
• 作者: Abt, I.;Gooch, C.;Hagemann, F.;Hauertmann, L.;Liu, X.;Schulz, O.;Schuster, M.
• 通讯作者: Schuster, M.

Large-scale, precision xenon doping of liquid argon

液氩的大规模、精密氙气掺杂

• DOI: 10.1016/j.nima.2021.165575
• 发表时间: 2021
• 期刊: Detectors and Associated Equipment
• 作者: McFadden, N.;Elliott, S.R.;Gold, M.;Fields, D.E.;Rielage, K.;Massarczyk, R.;Gibbons, R.
• 通讯作者: Gibbons, R.

Hydrogen reduction of enriched germanium dioxide and zone-refining for the LEGEND experiment

LEGEND 实验中富集二氧化锗的氢还原和区域精炼

• DOI: 10.1088/1748-0221/15/12/p12010
• 发表时间: 2020
• 期刊: Journal of Instrumentation
• 影响因子: 1.3
• 作者: Gradwohl, K.-P.;Moras, O.;Janicskó-Csáthy, J.;Schönert, S.;Sumathi, R.R.
• 通讯作者: Sumathi, R.R.

Calibration sources for the LEGEND-200 experiment

LEGEND-200 实验的校准源

• DOI: 10.1088/1748-0221/18/02/p02001
• 发表时间: 2023
• 期刊: Journal of Instrumentation
• 影响因子: 1.3
• 作者: Baudis, L.;Benato, G.;Bond, E.M.;Chiu, P.J.;Elliott, S.R.;Massarczyk, R.;Meijer, S.J.;Müller, Y.
• 通讯作者: Müller, Y.

Investigation of ASIC-based signal readout electronics for LEGEND-1000

• DOI: 10.1088/1748-0221/15/09/p09022
• 发表时间: 2020-05
• 期刊: Journal of Instrumentation
• 影响因子: 1.3
• 作者: F. Edzards;S. Mertens;L. Bombelli;G. Zuzel;D. Fink;S. Schönert;D. Radford;M. Green;M. Laubenstein;A. Alborini;G. Othman;M. Willers