CAREER: Beams of Fast Exotic Nuclei and the Origin of Heavy Elements in Stars

这个由核物理项目支持的教师早期职业发展（Career）项目，重点研究外来核粒子束的研究和教育。这项研究包括对具有极端中子质子比的不稳定核的实验研究。这些外来核靠近核滴线，即核素图中核子结合结束的位置。尽管核壳层在稳定谷附近很好地建立起来，但理论模型预测，随着核线的接近，常规核壳结构可能会发生剧烈变化。核结构的这种剧烈变化对我们理解恒星中的快中子捕获过程提出了特别的挑战。这个所谓的r过程是宇宙中超过一半比铁重的元素产生的原因。由于在r过程路径中对中子非常丰富的原子核的质量、半衰期和变形的测量非常稀少，目前使用理论模型来计算这些性质。由于缺乏非常富中子核的实验数据，目前使用的理论模型的预测能力未经检验。为了纠正这种情况，这里提出的研究将使用不同的实验技术来测量外来核的基本性质，这些外来核是在国家科学实验室由稳定原子核束的破碎产生的。提高各级的科学素养是拟议教育活动的目标。这项工作将集中在三个特定的目标群体：传统上在科学领域代表性不足的高中生、目前的大学预科科学教师和本科生（尤其是未来的教师）。提出了扩大国家科学实验室夏季外展计划（“原子核物理”）的建议。其目的是让来自传统上在科学领域代表性不足的群体的高中生在他们的职业生涯早期就能在一个活跃的研究环境中体验科学的兴奋和喜悦，以便他们可以选择从事科学事业。同时，邀请初高中科学教师到国家科学图书馆直接接触基础研究，并学习如何将基础研究成果融入课堂。在密歇根州立大学，对本科生的科学教育，特别是对未来教师的科学教育，都是在大课上进行的。在由首席研究员教授的大型课堂上，提出了一种积极的学习环境，利用现代技术教学助手。这种形式将从传统的、以教师为中心的课堂转变为互动的、以学生为中心的论坛，学生可以在论坛上审视自己的新想法，通过概念理解来学习，而不仅仅是听。这个互动环境的部分将突出国家科学实验室的基础核物理研究，从而强调通过与前沿基础研究的联系，介绍物理概念的相关性。

9875122GlasmacherThis Faculty Early Career Development (CAREER) project, supported in the Nuclear Physics Program, focuses on research and education with particle beams of exotic nuclei. The research encompasses an experimental study of unstable nuclei with an extreme neutron-to-proton ratio. These exotic nuclei are close to the nuclear driplines, the locus in the chart of nuclides where the binding of nucleons ends. Even though nuclear shells are well established close to the valley of stability, theoretical models have predicted the possibility of a drastic change of conventional nuclear shell structure as the nuclear driplines are approached. Such a dramatic change in nuclear structure poses particular challenges for our understanding of the rapid neutron capture process in stars. This so-called r-process accounts for the generation of more than half of all elements heavier than iron in the universe. Since measurements of masses, half-lives, and deformations on the very neutron-rich nuclei in the r-process path are extremely scarce, theoretical models are currently used to calculate these properties. In the absence of experimental data on very neutron-rich nuclei the predictive power of currently used theoretical models is untested. To remedy this situation, the research proposed here will use different experimental techniques to measure basic properties of exotic nuclei, produced at the NSCL by fragmentation of beams of stable nuclei. Enhancing scientific literacy at all levels is the goal of the proposed educational activities. This effort will focus on three specific target groups: high-school students traditionally underrepresented in science, current pre-college science teachers, and undergraduate students (especially prospective teachers). An expansion of the NSCL summer outreach program ("Physics of Atomic Nuclei") is proposed. The purpose is to allow high-school students from groups traditionally underrepresented in science to experience the excitement and joy of science in an active research environment early enough in their careers that they can choose to pursue a career in science. At the same time middle and high-school science teachers are invited to the NSCL to get direct exposure to basic research and to learn how they can integrate basic research results into their classes. At Michigan State University, science education of undergraduate students in general and prospective teachers in particular, takes place in large lecture classes. Implementation of an active learning environment that makes use of modern technological teaching aides in such large lecture classes taught by the principal investigator is proposed. The format will shift from a traditional, teacher-centered classroom toward an interactive, student-centered forum where students can examine their own and new ideas, learning through conceptual understanding rather than listening alone. Segments in this interactive environment will highlight basic nuclear physics research at the NSCL and thus emphasize the relevance of introductory physics concepts through their connection to cutting-edge basic research.