Collaborative Research: RUI: Study of Exotic Nuclei and Neutron Detector Response

合作研究：RUI：奇异核和中子探测器响应的研究

• 批准号: 2011398
• 负责人: Anthony Kuchera
• 金额: $ 17.67万
• 依托单位: Davidson College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2011398&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Study; Exotic

The main goal of this experimental program is to advance understanding of the nature of exotic atomic nuclei, with undergraduate student participation as an integral component. Experiments will be conducted at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) using the Modular Neutron Array (MoNA) and the Large-area multi-Institutional Scintillator Array (LISA), both constructed and tested by undergraduate students from several institutions in the MoNA collaboration. The PIs of this award and their team of undergraduate students will investigate the structure of light neutron-rich nuclei near the limits of stability, which will provide data to test current theoretical models of nuclear structure. As the nuclear mass-to-charge ratio for isotopes of an element increases, the isotopes become weakly-bound or unbound, and they exhibit significantly different structure compared with their stable counterparts. These unstable nuclei are produced by collisions of an accelerated nuclear beam with a stable target, and accurate computer simulations of neutron scattering in the MoNA-LISA plastic scintillator detectors are critical for extracting physics results from the breakup of these short-lived nuclei. Analysis of recent neutron-scattering experiments conducted at Los Alamos National Laboratory will improve accuracy of these simulations in preparation for higher energy experiments soon to be conducted at the Facility for Rare Isotope Beams (FRIB) at MSU. Broader impacts of the proposed work include formative research opportunities for undergraduate students and investing in the MoNA Collaboration in terms of equipment development and leadership.Research supported by this award will consist of conducting two new experiments, analyzing recent and future data, and contributing to the development of the next generation fast neutron detector for use with the High-Rigidity Spectrometer at FRIB. Two final MoNA experiments at the NSCL will be performed in 2020 to study neutron-unbound states in neutron-rich nuclei. The nuclei of interest are 13Be and 28F. These experiments will resolve the longstanding issue of the level structure of 13Be, which is in the N=8 region of the nuclear chart known for structural changes, and measurements of unbound 28F states combined with previously determined two-body matrix elements from 28F will help place limits on the one-neutron separation energy of 28O. To prepare for experiments at the upcoming FRIB facility, an experiment was performed at the Los Alamos Neutron Science Center (LANSCE) in November 2019 to measure neutron scattering and secondary neutron production during the interaction of fast neutrons with plastic scintillator detectors. This work will add to the recent neutron scattering work from the PIs which exposed some failures of current GEANT4-based Monte Carlo simulation packages. The goal is to improve the modeling of neutron interactions with these detectors, which will be crucial for improving detector resolution and filtering of data for FRIB experiments. The work also serves a broader community since plastic scintillators are widely used for neutron detection in nuclear physics and related applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该实验计划的主要目标是加深对奇异原子核性质的理解，本科生的参与是不可或缺的组成部分。实验将在密歇根州立大学 (MSU) 的国家超导回旋加速器实验室 (NSCL) 进行，使用模块化中子阵列 (MoNA) 和大面积多机构闪烁体阵列 (LISA)，这两种阵列均由来自密歇根州立大学的本科生构建和测试。多个机构参与了 MoNA 的合作。该奖项的 PI 及其本科生团队将研究稳定极限附近的轻中子富核结构，这将为测试当前的核结构理论模型提供数据。随着元素同位素的核质荷比增加，同位素变得弱结合或未结合，并且与稳定的同位素相比，它们表现出显着不同的结构。这些不稳定的原子核是由加速核束与稳定目标碰撞产生的，MoNA-LISA 塑料闪烁体探测器中中子散射的精确计算机模拟对于从这些短命原子核的分裂中提取物理结果至关重要。对最近在洛斯阿拉莫斯国家实验室进行的中子散射实验的分析将提高这些模拟的准确性，为即将在密歇根州立大学稀有同位素束设施 (FRIB) 进行的更高能量实验做准备。 拟议工作的更广泛影响包括为本科生提供形成性研究机会，以及在设备开发和领导力方面对 MoNA 合作进行投资。该奖项支持的研究将包括进行两项新实验，分析最近和未来的数据，并为开发下一代快中子探测器，与 FRIB 的高刚性能谱仪一起使用。 MoNA 的最后两项实验将于 2020 年在 NSCL 进行，以研究富中子核中的中子游离态。感兴趣的原子核是 13Be 和 28F。这些实验将解决长期存在的 13Be 能级结构问题，该结构位于以结构变化而闻名的核图 N=8 区域，并且对未结合 28F 态的测量与先前确定的 28F 的二体矩阵元素相结合将有助于对 28O 的单中子分离能进行限制。为了为即将建成的 FRIB 设施的实验做准备，洛斯阿拉莫斯中子科学中心 (LANSCE) 于 2019 年 11 月进行了一项实验，以测量快中子与塑料闪烁体探测器相互作用过程中的中子散射和二次中子产生。这项工作将补充最近 PI 的中子散射工作，该工作暴露了当前基于 GEANT4 的蒙特卡罗模拟软件包的一些故障。目标是改进中子与这些探测器相互作用的建模，这对于提高探测器分辨率和 FRIB 实验数据过滤至关重要。这项工作还服务于更广泛的社区，因为塑料闪烁体广泛用于核物理和相关应用中的中子探测。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Mirror nucleon removal reactions in p -shell nuclei

p 壳核中的镜像核子去除反应

• DOI: 10.1103/physrevc.105.034314
• 发表时间: 2022-03
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Kuchera, A. N.;Bazin, D.;Phan, T.;Tostevin, J. A.;Babo, M.;Baumann, T.;Bender, P. C.;Bowry, M.;Bradt, J.;Brown, J.;et al
• 通讯作者: et al

Neutron-unbound states in Ne31

Ne31 中的中子游离态

• DOI: 10.1103/physrevc.104.034313
• 发表时间: 2021-09
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Chrisman, D.;Kuchera, A. N.;Baumann, T.;Blake, A.;Brown, B. A.;Brown, J.;Cochran, C.;DeYoung, P. A.;Finck, J. E.;Frank, N.;et al
• 通讯作者: et al