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; 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提高对外来原子核的性质的理解，并以学生的本科参与为组成部分。实验将在密歇根州立大学（MSU）的国家超导式回旋实验室（NSCL）进行，使用模块化的中子阵列（MONA）和大区域的多机构闪光阵列（LISA），由多个机构的MONA协作中的几个机构进行了建造和测试。该奖项的PI及其本科生团队将研究稳定范围附近的光中子核的结构，这将提供数据以测试当前的核结构理论模型。随着元素同位素增加的核质量质量比率增加，同位素变得较弱或未结合，并且与稳定的对应物相比，它们表现出明显不同的结构。这些不稳定的核是通过与稳定靶标的加速核束的碰撞产生的，并且在Mona-Lisa塑料闪烁体检测器中对中子散射的准确计算机模拟对于从这些短暂的核的破裂中提取物理结果至关重要。分析在Los Alamos国家实验室进行的最新中子散射实验将提高这些模拟的准确性，以准备更高的能量实验，以准备在MSU的稀有同位素束（FRIB）的设施中进行的更高能量实验。 拟议工作的更广泛的影响包括针对本科生的形成性研究机会以及在设备开发和领导方面投资于MONA协作。该奖项的支持将包括进行两个新的实验，分析最近和未来的数据，并为下一代快速中子检测器的开发提供助长，以在FRIB上使用高级实验表。 NSCL的两个最终MONA实验将在2020年进行研究，以研究富含中子的核中的中子脉状状态。感兴趣的核为13BE和28F。这些实验将解决13BE级别结构的长期问题，该水平结构在核图的n = 8区域中已知的结构变化已知，并测量未结合的28F状态以及先前确定的28F的两体矩阵元素将有助于对28O的单人体分离能量限制。为了准备在即将到来的FRIB设施上进行实验，2019年11月在Los Alamos中子科学中心（LANSCE）进行了一个实验，以测量中子与塑料闪烁剂探测器的快速中子相互作用期间的中子散射和二次中子产生。这项工作将增加PI的最新中子散射工作，这暴露了当前基于GEANT4的蒙特卡洛模拟包的某些故障。目的是改善与这些检测器的中子相互作用的建模，这对于改善检测器的分辨率和FRIB实验的数据过滤至关重要。这项工作也为更广泛的社区提供服务，因为塑料闪烁体被广泛用于核物理和相关应用中的中子检测。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响评估标准，认为值得通过评估值得支持。