Nuclear Reactions with Short-Lived Nuclear Beams

短命核束的核反应

• 批准号: 0652591
• 负责人: Fred Becchetti
• 金额: --
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0652591&HistoricalAwards=false
• 关键词: Nuclear; Reactions; Short; Lived; Beams

The proposed project will involve the study of nuclear reactions utilizing short-lived radioactive nuclear beams (RNBs) together with the development of instrumentation, techniques, and apparatus to facilitate RNB studies. Specific experiments will emphasize the investigation of the structure and reaction mechanisms of neutron- and proton-rich nuclei near the limits of nuclear stability using low-energy nuclear reactions with short-lived beams such as 6He, 8Li, 7Be, 8B, etc.. These studies are a continuation of a very successful program to elucidate the effect that the exotic "nuclear halo" structure, which appears for weakly-bound systems at the limits of stability, has on fusion, transfer, inelastic excitation, and breakup probabilities near the Coulomb barrier. Of particular interest here is the influence that higher-order couplings to and within the continuum have on the various reaction mechanisms, since proximity of the continuum is one of the characteristic, defining features of weakly-bound systems. The work will be carried out primarily with the TwinSol facility at the University of Notre Dame (UND), although the RNB facilities at Oak Ridge National Laboratory and (possibly) at the National Superconducting Cyclotron Laboratory may also be utilized for specific experiments. We also propose to make use of the nearly unique capabilities of the beams and experimental equipment available at UND to very accurately measure the (3He,n) reaction on Ge isotopes. The data obtained from this experiment, when combined with the results from other experiments already underway at Yale University, will enable a much-improved value for the nuclear matrix element relevant for neutrinoless double decay of 76Ge. This in turn will allow for a more accurate determination of the mass of the neutrino.The broader impact of the proposal on graduate, undergraduate, and high school education, as well as the development of a technologically literate workforce, is as follows. The proposed work will involve graduate and undergraduate students from the University of Michigan (UM) and the University of Notre Dame, together with faculty members and students from several other (primarily undergraduate) schools located in close proximity to UM and UND. The "hands-on" training of these students in the use of advanced, state-of-the-art computational methods, nuclear accelerators, radiation detectors, vacuum and cryogenic techniques, and superconducting ion-optical magnetic systems has already had an important impact on the development of a technologically-literate workforce. Finally, we will continue and expand a highly successful program that involves high-school students from the socio-economically-challenged New Buffalo, MI school district in physics-related research. This program has three components: the development of a nuclear-physics curriculum at NBHS that satisfies State of Michigan standards in this area, a yearly tour of the Notre Dame nuclear physics laboratory by all the physical-sciences students at NBHS, and a one-week residential "nuclear physics summer camp" for selected (and highly-motivated) NBHS students interested in learning about careers in physics. The summer program is arranged so that the students can interact directly with physics graduate and undergraduate students, and faculty from several nearby colleges and universities who can share their knowledge and experiences of physics as a career.

拟议的项目将涉及利用短寿命放射性核束（RNB）研究核反应，以及开发仪器，技术和设备，以促进RNB研究。 具体的实验将强调的结构和反应机制的中子和质子丰富的核附近的核稳定性使用低能量的核反应与短寿命的光束，如6He，8Li，7Be，8B等的调查。这些研究是一个非常成功的计划的延续，阐明了外来的“核晕”结构，这似乎是弱约束系统的稳定性的极限，对融合，转移，非弹性激发，和崩溃的几率库仑势垒附近的效果。 这里特别感兴趣的是，高阶耦合和连续内的各种反应机制的影响，因为连续的接近是一个特征，定义功能的弱约束系统。 这项工作将主要利用圣母大学的TwinSol设施进行，但橡树岭国家实验室和（可能）国家超导回旋加速器实验室的RNB设施也可用于具体实验。 我们还建议利用UND的光束和实验设备的几乎独特的能力，非常准确地测量Ge同位素的（3He，n）反应。 从这个实验中获得的数据，当与耶鲁大学已经在进行的其他实验的结果相结合时，将使与76Ge的无中微子双衰变相关的核矩阵元素的值得到很大的改进。 这反过来将允许更准确地确定中微子的质量。该提案对研究生、本科生和高中教育以及技术素养劳动力的发展的更广泛影响如下。 拟议的工作将涉及密歇根大学（UM）和圣母大学的研究生和本科生，以及位于UM和UND附近的其他几所学校（主要是本科生）的教师和学生。 这些学生在使用先进的、最先进的计算方法、核加速器、辐射探测器、真空和低温技术以及超导离子光磁系统方面的“动手”培训已经对培养具有技术素养的劳动力产生了重要影响。 最后，我们将继续和扩大一个非常成功的计划，涉及高中学生从社会经济挑战新水牛，密歇根州学区在物理相关的研究。该计划有三个组成部分：在NBHS的核物理课程的发展，满足密歇根州在这方面的标准，每年参观圣母院核物理实验室的所有物理科学的学生在NBHS，和一个为期一周的住宅“核物理夏令营”为选定的（和高度积极性）NBHS学生有兴趣学习有关物理职业。暑期课程的安排，使学生可以直接与物理研究生和本科生互动，以及来自附近几所学院和大学的教师谁可以分享他们的知识和经验的物理作为一个职业。