Nuclear Reactions to Probe Structure of Exotic Nuclei

核反应探测奇异核的结构

• 批准号: 1404218
• 负责人: Jolie Cizewski
• 金额: $ 39万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1404218&HistoricalAwards=false
• 关键词: Nuclear; Reactions; Probe; Structure; Exotic

Experimental nuclear physics helps us to understand the properties of the nuclei at the center of atoms and how the elements are synthesized in stars and their explosions. This project enhances our understanding of these fundamental questions by accelerating nuclei to high energies and measuring gamma and charged particle radiation that is emitted when they interact with other atomic nuclei. The focus is on accelerating beams of atomic nuclei that are unstable to beta decay, living for times as short as seconds. The interactions between atomic nuclei informs our understanding of the properties of atomic nuclei, especially those far from stability that are more weakly bound, as well as helping us to understand how the parents of the stable elements were synthesized. The project exploits state-of-the-art instruments and accelerator facilities in the U.S. Central to this effort is enhancing the education of students and postdoctoral scholars and preparing them for careers in education and fundamental and applied research. The nuclear physics results from this project are also of importance in astronomy, to understand the abundance of elements observed in the cosmos, and for nuclear energy and national security, to understand properties of and reactions on fragments from fission of actinides. To expand the reach of this project, the principal investigator presents workshops to undergraduate students on how to prepare for graduate studies and gives lectures to the public and schools on this research.One of the frontier areas of nuclear physics is the study of the structure of atomic nuclei far from the valley of stability. In atomic nuclei the single-particle orbitals are expected to change as a function of neutron and proton number, and in addition are very sensitive to the presence of deformation. Single-particle characteristics can be probed in single-particle transfer reactions. Light-ion transfer reactions will be studied with beam energies near the Coulomb barrier and about 35-MeV per nucleon. Studies will concentrate on neutron-rich nuclei near the N=50 neutron shell closure, accelerated fragments following fission of 252Cf and light nuclei important for understanding the synthesis of nuclei in stars and their explosions. These studies will be carried out with accelerated beams of rare isotopes at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University and the Argonne Tandem Linac Accelerator System (ATLAS) at Argonne National Laboratory. The NSCL focus is to extract spectroscopic strengths with reduced dependence on theoretical model parameters. At ATLAS the group will exploit Gammasphere-ORRUBA: Dual Detectors for Nuclear Structure Studies to probe the fragmentation of single-particle strength with coincidence measurements between charged particles (measured with ORRUBA, the Oak Ridge Rutgers University Barrel Array of position-sensitive silicon strip detectors) and gamma rays (measured with Gammasphere, the array of 110 Compton-suppressed Ge gamma-ray detectors). The group will also further develop capabilities to measure particle-gamma-ray coincidences with scintillator detectors coupled to ORRUBA.

实验核物理帮助我们了解原子中心原子核的性质以及元素如何在恒星及其爆炸中合成。该项目通过将原子核加速到高能量并测量与其他原子核相互作用时发出的伽马和带电粒子辐射，增强了我们对这些基本问题的理解。重点是加速对β衰变不稳定的原子核束，其寿命短至几秒。原子核之间的相互作用让我们了解原子核的性质，特别是那些远离稳定、束缚较弱的原子核的性质，并帮助我们了解稳定元素的母体是如何合成的。该项目利用美国中央最先进的仪器和加速器设施，旨在加强学生和博士后学者的教育，并为他们从事教育、基础和应用研究职业做好准备。 该项目的核物理结果对于天文学、了解宇宙中观察到的元素丰度、了解核能和国家安全、了解锕系元素裂变碎片的性质和反应也具有重要意义。为了扩大该项目的影响范围，首席研究员为本科生举办了关于如何为研究生学习做准备的研讨会，并向公众和学校就这项研究进行了讲座。核物理的前沿领域之一是核物理结构的研究原子核远离稳定谷。 在原子核中，单粒子轨道预计会随着中子和质子数的函数而变化，此外对变形的存在非常敏感。 可以在单粒子转移反应中探测单粒子特征。轻离子转移反应将在库仑势垒附近和每个核子约 35 MeV 的束流能量下进行研究。研究将集中于 N=50 中子壳层闭合附近的富中子核、252Cf 裂变后的加速碎片以及对于理解恒星中核的合成及其爆炸非常重要的轻核。这些研究将在密歇根州立大学国家超导回旋加速器实验室 (NSCL) 和阿贡国家实验室阿贡串联直线加速器系统 (ATLAS) 中使用稀有同位素加速束进行。 NSCL 的重点是提取光谱强度，减少对理论模型参数的依赖。 在 ATLAS，该小组将利用 Gammasphere-ORRUBA：用于核结构研究的双探测器，通过带电粒子之间的重合测量来探测单粒子强度的碎片（使用 ORRUBA 进行测量，ORRUBA 是橡树岭罗格斯大学位置敏感硅条探测器桶阵列） ）和伽马射线（用 Gammasphere 测量，Gammasphere 是由 110 个康普顿抑制 Ge 伽马射线探测器组成的阵列）。 该小组还将进一步开发使用与 ORRUBA 耦合的闪烁体探测器测量粒子伽马射线重合的能力。

项目成果

Neutron-hole states in 131Sn and spin-orbit splitting in neutron-rich nuclei

131Sn 中的中子空穴态和富中子核中的自旋轨道分裂

• DOI: 10.1016/j.physletb.2018.08.005
• 发表时间: 2018-10-01
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: R. Orl;i;i;S. Pain;S. Ahn;A. Jungclaus;K. Schmitt;D. Bardayan;W. Catford;R. Chapman;K. Chipps;J. Cizewski;C. G. Gross;M. Howard;K. L. Jones;R. Kozub;B. Manning;M. Matoš;K. Nishio;P. D. Malley;W. Peters;S. T. Pittman;A. Ratkiewicz;C. Sh;J. Smith;M. Smith;T. Fukui;J. Tostevin;Y. Utsuno
• 通讯作者: Y. Utsuno

Development of an array of liquid-scintillator-based bar detectors: SABRE

开发一系列基于液体闪烁体的条形探测器：SABRE

• DOI: 10.1016/j.nima.2018.08.051
• 发表时间: 2018-11
• 期刊: Detectors and Associated Equipment
• 作者: Febbraro, M.;Walter, D.;Chipps, K.A.;Pain, S.D.;Temanson, E.;Toomey, R.;Atencio, A.;Thornsberry, C.R.;Smith, K.;O’Neill, J.;et al
• 通讯作者: et al