Neutrino-Less Double Beta Decay with EXO-200 and EXO

EXO-200 和 EXO 的无中微子双贝塔衰变

• 批准号: 1209907
• 负责人: Andrea Pocar
• 金额: $ 60.9万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1209907&HistoricalAwards=false
• 关键词: Neutrino; Less; Double; Beta; Decay

This award provides base support for the group to continue to participate in the Enriched Xenon Observatory (EXO) program to search for neutrino-less double beta decay in 136-Xenon, a nuclear process which could hold clues into the nature of neutrinos. Observation of this decay would imply that neutrinos are Majorana particles, i.e. their own antiparticles, with profound implications on our understanding of the pattern of masses of fundamental particles and of the structure and evolution of the early universe. The EXO-200 experiment, a 200-kg enriched liquid xenon detector is now running underground at the Waste Isolation Pilot Plant (WIPP) in New Mexico. This group will also take part in the development and design of a more sensitive tonne-scale EXO experiment (full-EXO) to follow EXO-200. With the planned research at UMass, the group will provide key input to the design of a full-EXO experiment with sensitivity to neutrino masses as small as 10 meV by: i) optimizing the optical response and VUV detection efficiency of the detector, and ii) supplying a single Barium ion source, a possibly game-changing tool for the realization of the EXO-specific background suppression scheme which looks for the appearance of Barium ions following 136-Xe double beta decay.Broader Impacts: Noble liquid detectors are finding applications in medical imaging devices as well as in remote monitoring of nuclear power plant fuel composition. The ultra-low background methods developed for detectors like EXO-200 have taken radioactive contamination to levels considered impossible to achieve just twenty years ago. Processes of interest for the electronics industry now require similar levels of radio-purity in their manufacturing lines. Work with EXO-200 and EXO provides ample opportunities for graduate students to perform cutting edge research and experience working in a medium-sized international scientific collaboration.

该奖项为该小组继续参与浓缩氙天文台（EXO）计划提供了基础支持，该计划旨在寻找136-氙中的无中微子双β衰变，这是一种核过程，可以为中微子的性质提供线索。对这种衰变的观察意味着中微子是马约拉纳粒子，即它们自己的反粒子，这对我们理解基本粒子的质量模式以及早期宇宙的结构和演化具有深远的意义。EXO-200实验，一个200公斤的浓缩液体氙探测器，现在正在新墨西哥州的废物隔离试验工厂（WIPP）的地下运行。该小组还将参与开发和设计继EXO-200之后的更灵敏的吨级EXO实验（全EXO）。随着计划在马萨诸塞大学的研究，该小组将提供关键输入的设计一个完整的EXO实验与灵敏度中微子质量小到10毫电子伏：i）优化检测器的光学响应和VUV检测效率，以及ii）提供单个钡离子源，一个可能改变游戏规则的工具，用于实现特定于EXO的背景抑制方案，该方案在136- 2000年之后寻找钡离子的出现。更广泛的影响：稀有液体探测器在医学成像设备以及核电站燃料成分的远程监测中得到了应用。为EXO-200等探测器开发的超低本底方法已经将放射性污染水平提高到了20年前被认为不可能达到的水平。电子工业的相关工艺现在需要在其生产线中达到类似水平的放射性纯度。与EXO-200和EXO的工作为研究生提供了充足的机会，在中型国际科学合作中进行尖端研究和工作经验。