Purification of the Ge-76 for the Majorana Demonstrator

一个全面的计划，在中微子少双β衰变是非常及时的。美国物理学会多部门研究的一个主要结论指出：“我们建议，作为一个高度优先事项，对中微子较少的核双β衰变进行分阶段的灵敏搜索。这个项目的智力价值来自于这样一个事实，即中微子较少的核双β衰变“是确定中微子是否是马约拉纳粒子（它们自己的反粒子）的唯一实用方法”。这种奇特的核衰变是轻子数守恒最敏感的测试，轻子数守恒是基本粒子物理学中的一个重要对称性。事实上，如果中微子是马约拉纳粒子，精确测量无中微子核双β衰变半衰期是可能的;它将产生电子中微子的有效马约拉纳质量。当与中微子振荡数据相结合时，它将确定所有三个中微子质量本征值。该奖项提供资金支持马约拉纳研发项目的一项主要任务，以确定一吨76 Ge无中微子核双β衰变实验的可行性和成本。一吨实验所需的富集锗的纯化和再循环必须有效地进行，以大大降低实验成本。该计划包括购买所需的设备，安装，雇用和培训人员，测试天然丰度锗的操作，处理MAJORANA演示模块的浓缩76 Ge，并优化效率。更广泛的影响之一是，国家和国土安全的新探测器技术和其他基础/应用科学的新探测器技术。

A comprehensive program in neutrino-less double-beta decay is very timely. A principal conclusion of the APS Multidivisional Study stated: "We recommend, as a high priority, a phased program of sensitive searches for neutrino-less nuclear double-beta decay." The intellectual merit of this project derives from the fact that neutrino-less nuclear double-beta-decay "is the only practical way to determine if neutrinos are Majorana particles (their own antiparticles)". This exotic nuclear decay is the most sensitive test of lepton-number conservation, an important symmetry in elementary-particle physics. In fact, if neutrinos are Majorana particles, an accurate measurement of the neutrino-less nuclear double-beta-decay half-life might well be possible; it would yield the effective Majorana mass of the electron neutrino. When combined with neutrino oscillation data, it would determine all three neutrino-mass eigenvalues. This award provides funding to support a major Task in the MAJORANA R&D Project to establish the feasibility and cost of a one-ton 76Ge neutrino-less nuclear double-beta-decay experiment. The purification and recycling of the quantity of enriched germanium required for a one-ton experiment will have to be done efficiently to significantly reduce the cost of the experiment. The plan involves purchasing the needed equipment, setting it up, hiring and training personnel, testing the operation with natural abundance germanium, and processing the enriched 76Ge for the MAJORANA Demonstrator Module, and optimizing the efficiency. Among the broader impacts is, and has been, new detector technology for national and homeland security and new detector technology for other basic/applied sciences.