The EXO search for Neutrino-less Double Beta Decay

EXO 寻找无中微子双贝塔衰变

• 批准号: SAPPJ-2017-00029
• 负责人: Farine, Jacques
• 金额: $ 13.55万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=694091
• 关键词: EXO; search; Neutrino; less; Double

This application seeks support for the EXO program searching for neutrino less double beta decay in xenon. The proposed work is comprised of three main, tightly coupled, activities: work on the existing 200 kg detector, EXO-200; work to establish the first detector to explore the inverted hierarchy, nEXO; and work to find a roadmap to reach the normal hierarchy.******We are participating in the operation and exploitation of the EXO-200 detector. This pioneering detector was the first to reach sensitivity at the hundred kilogram scale and with this detector we have made the first observation of the two neutrino decay of 136Xe. We established a limit for the neutrino less decay mode which at the time was a world record and it was the first measurement to seriously challenge the claimed observation of this decay process by the Heidelberg-Moscow collaboration. It has been decided to operate for another three years to get an improvement of about a factor of 3 in the sensitivity to double beta decay. This will again make the detector comparable in sensitivity to the best in the world. This work also provides physics topics for our students and research associates.******The second part of the work is the development of the design for the proposed 5 tonne detector nEXO, that the collaboration plan to install at SNOLAB. If approved this should be the world's most sensitive detector for this critical physics study and would provide coverage of the entire inverted hierarchy region of neutrino masses. While the detector has its basis in the EXO-200 design, there are a number of area where improvements can be made in the design or where the design of the 200 kg detector does not scale nicely to the tonne scale. The Canadian team has been very active in this process. We have undertaken major responsibilities for the light sensitive system which will employ SiMs. Another area of responsibility is the design of calibration delivery systems. These activities form a major part of our activities for the coming period. We have also started to explore if less expensive techniques can be found to enrich the xenon. Specifically, we will carry out studies to see if the vapour pressure differences of the xenon isotopes are large enough to permit separation by distillation.******Finally the group is looking ahead to develop concepts for detectors that can reach the normal hierarchy. One of the techniques we have been exploring is to tag each event with the presence of otherwise of a daughter barium ion. We have developed concepts for this and have been successfully testing each of the steps in the process but now we must combine the steps to study a complete process. It will be critical to understand the overall efficiency for the process and to measure any inherent backgrounds to the measurement.

这个应用程序寻求支持EXO计划寻找氙中的中微子少双β衰变。拟议的工作由三个主要的紧密耦合的活动组成：现有200公斤探测器EXO-200的工作;建立第一个探测器以探索倒置层次的工作，nEXO;以及寻找达到正常层次的路线图。我们正在参与EXO-200探测器的操作和开发。这个开创性的探测器是第一个达到100公斤级灵敏度的探测器，我们用这个探测器首次观测到了136的两个中微子衰变。我们为中微子较少的衰变模式建立了一个极限，这在当时是一项世界纪录，这是第一次测量严重挑战海德堡-莫斯科合作对这种衰变过程的观测。 已决定再运行三年，以使灵敏度提高约3倍。 β衰变这将再次使探测器的灵敏度与世界上最好的探测器相媲美。这项工作也为我们的学生和研究提供了物理课题 我是律师工作的第二部分是开发拟议的5吨探测器nEXO的设计，该合作计划安装在SNOLAB。如果获得批准，这将是世界上最灵敏的探测器，用于这项临界物理研究，并将覆盖整个中微子质量的倒置层次区域。虽然探测器以EXO-200设计为基础，但在设计方面仍有许多地方可以改进，或者200公斤探测器的设计不能很好地按吨级进行缩放。加拿大队在这一进程中非常积极。 我们承担了使用西姆斯的光敏系统的主要责任。 另一个责任领域是校准交付系统的设计。这些活动是我们今后活动的主要部分。我们还开始探索是否可以找到更便宜的技术来富集氙气。具体来说，我们将进行研究，看看氙同位素的蒸汽压差是否足够大，可以通过蒸馏进行分离。最后，该小组正在展望未来，开发可以达到正常层次的探测器概念。我们一直在探索的技术之一是标记每个事件的存在，否则的子钡离子。我们已经为此开发了概念，并成功地测试了过程中的每个步骤，但现在我们必须将这些步骤结合起来研究一个完整的过程。了解流程的整体效率并测量测量的任何固有背景将是至关重要的。