Studies of Exotic Nuclei with the MoNA LISA Neutron Detectors

中密歇根大学的一名教师和他的本科生合作建造、组装和测试了2004年完成的价值100万美元的模块化中子阵列（莫纳）。随后，该合作获得了130万美元的NSF赠款，用于建造大型多机构闪烁体阵列（丽莎）。在国家超导回旋加速器实验室（NSCL），莫纳丽莎中子探测器串联与扫掠器磁铁一起使用。莫纳丽莎的主要目的是提取中子未束缚核的质量和未束缚态的激发能。要解决的物理问题是位于滴线附近甚至更远的轻的、非常富含中子的核。这是非常弱结合的核子物质的领域，在那里已经观察到了迷人的新现象，如晕或壳结构的剧烈变化。莫纳丽莎和Sweeper探测系统非常适合通过研究近滴线核的基态和低激发态的性质来探索其本征结构。它还将提供有关位于滴线及更远处的原子核中粒子发射阈值上方的低位共振的信息。最后，探测器的设计方式，他们可以很容易地测量中子的巧合，使发射的中子之间的相关性，可以investigedin细节，以及。莫纳合作是在一个独特的情况下，这是完全不同于任何其他合作或研究小组提出的实验在NSCL。具体来说，它首先允许来自主要本科院校的教授及其本科生参与顶级研究仪器的建设。本集团应对了从建设向生产转型的挑战。我们已经建立了一个独特的分析方案，允许本科课程参与莫纳实验的运行，还原和分析。因此，112名本科生有机会参加尖端的核物理实验。此外，中密歇根大学积极努力让高中生和他们的老师接触实验核物理，甚至把莫纳带到密歇根州的立法者和他们的工作人员那里。

A faculty member and his undergraduates at Central Michigan University were collaborators in the construction, assembly, and testing of the one million dollar Modular Neutron Array (MoNA) which was completed in 2004. Subsequently, the collaboration received a $1.3 Million NSF grant to construct the Large multi-Institutional Scintillator Array (LISA). The MoNA LISA neutron detector tandem is used with the Sweeper magnet at the National Superconducting Cyclotron Laboratory (NSCL). The main purpose of MoNA LISA is to extract masses of neutron-unbound nuclei and excitation energies of unbound states. The physics to be addressed is that of light, very neutron-rich nuclei located in the direct vicinity of the drip line or even beyond. This is the domain of very weakly bound nucleonic matter where fascinating new phenomena have already been observed, such as halos or drastic changes in shell structure. The MoNA LISA and Sweeper detection system is ideally suited to explore the intrinsic structure of near drip line nuclei by studying the properties of their ground and low excited states. It will also provide information about low-lying resonances located just above the particle emission threshold in nuclei at the drip line and beyond. Finally, the detectors are designed in such a way that they can readily measure neutrons in coincidence so that correlations between emitted neutrons can be investigatedin detail as well.The MoNA collaboration is in a unique situation that is quite different from any other collaboration or research group proposing experiments at the NSCL. Specifically it first allowed professors from predominantly undergraduate institutions and their undergraduate students to participate in the construction of a top-level research instrument. The group has answered the challenge to transform from construction to production. We have built a unique analysis scheme that allows the undergraduate programs to be involved in the running, reduction, and analysis of MoNA experiments. As a result, 112 undergraduates have had the opportunity to participate in cutting-edge nuclear physics experiments. Additionally, Central Michigan University has aggressively worked to expose high school students and their teachers to experimental nuclear physics, and has even brought MoNA to Michigan state legislators and their staffs.