Collaborative research for DUSEL: Barium tagging in liquid xenon for EXO

EXO是一项使用136-Xe的吨级无中微子双β衰变实验，在这类实验中是独一无二的，因为它使用了一种新技术来标记双β衰变的终态(BA)产生的原子物种。这项技术有望极大地减少放射性背景，提供一种干净、明确、具有前所未有的灵敏度的测量方法。在过去的几年里，EXO的研发被平均分配给了建造一个200公斤的中等规模的探测器(EXO-200)，而不加BA标签的系统的开发。Exo-200的建造现已接近完成。本文的工作主要集中在从液体氙气(LXE)中提取和鉴定。文中提出的一些新想法有可能为全尺寸EXO实验的设计提供关键。以前的研发已经导致了一种离子陷阱，能够在有冷却气体存在的情况下清除单一的Ba离子，并对一些Ba转移技术进行了初步实验。这里提出的研发将围绕三个平行的主题，每个主题将由三个合作机构中的一个开发。随着EXO-200探测器的成功运行以及EXO-200标签研发的完成，将在不久的将来设计出一种强大的下一代双贝塔探测器，并将安装在地下实验室中。该项目将开发的技术涵盖了从核和粒子天体物理到AMO、表面物理和材料科学的广泛主题。这项研究如果成功，很可能适用于科学技术中的其他问题，在这些问题中，单原子的高效转移和识别将是令人感兴趣的。例如，用于国土安全应用的痕迹分析和罕见现象的检测。

EXO is a ton-class neutrino-less double beta decay experiment employing 136-Xe and is unique among such experiments as it utilizes a novel technique to tag the atomic species produced in the final state (Ba) of the double beta decay using laser spectroscopy. This technique has the promise of drastically reducing radioactive backgrounds, providing a clean and un-ambiguous measurement with unprecedented sensitivity. In the last few years, EXO R&D has been equally divided between the construction of a 200 kg intermediate scale detector (EXO-200) without Ba tagging and the development of the Ba tagging system. EXO-200 construction is now nearing completion. The work proposed here concentrates on Ba extraction from the liquid xenon (LXe) and identification. Some new ideas, presented here, have the potential of providing the key for the design of the full scale EXO experiment. Previous R&D has resulted in an ion trap capable of clear single Ba ion detection in the presence of a cooling gas, and the initial experimentation with a number of Ba transfer techniques. The R&D proposed here will revolve around three parallel themes, each to be developed by one of the three collaborating institutions. The conclusion of EXO Ba tagging R&D, along with the successful operation of the EXO-200 detector, will result in the design of a formidable next generation double beta detector to be sited at an underground laboratory in the near future. The techniques to be developed in this project span a broad range of topics, from nuclear and particle astrophysics, to AMO, surface physics and material science. This research, if successful, is likely to be applicable to other problems in science and technology, where the high efficiency transfer and identification of single atoms would be of interest. Examples include trace analysis for homeland security applications and the detection of rare phenomena.