Nuclear Structure and Nuclear Astrophysics

圣母大学核科学实验室(NSL)的这项研究计划解决了核天体物理、核结构物理和核物理应用中的关键问题。将在NSL加速器上使用伽马和粒子探测技术进行低能核反应测量，以确定确定静态和爆炸性恒星燃烧过程的核合成和时间尺度的反应截面和反应速率。用低能稳定束测量恒星反应的截面在亚纳米量级，主要受到宇宙和自然本底辐射的阻碍。对恒星爆炸中的核过程的研究依赖于由巴黎圣母院TwinSol设施或美国或欧洲其他稀有同位素加速器提供的强放射性束流。利用新的圣乔治反冲分离器，结合目前正在安装的新的低能重离子加速器，将开发新的实验方法和技术。核结构程序解决了原子核中奇异的转动和振动激发模式的问题，这将有助于更好地了解核物质的基本特征，并研究预测核少数体系统的新的量子现象模式。该计划还包括对许多天体物理现象至关重要的测量，如核物质的不可压缩性，这对我们理解中子星很重要；核的质量测量对各种恒星过程，特别是对理解重核的形成非常重要。该计划的目标是研究控制大质量恒星中元素的时间尺度、演化和形成的核反应。还将研究驱动恒星爆炸的反应，如新星和超新星，形成从铁到铅的重元素。这些研究将与恒星环境的计算机模拟相结合，以研究这些反应对第一代和以后一代恒星中观测到的元素丰度的影响。所有这些结果将使我们更好地了解元素的起源以及与我们宇宙相关的化学史。对于天文学家来说，这些结果将导致识别新的观测信号，如从恒星核心发出的中微子，超新星爆炸产生的长寿命放射性同位素，或从爆炸的中子星外壳发出的引力波。该项目涉及大量研究生和本科生，为美国国家实验室、大学、医疗设施和行业的核物理、核医学、核能、辐射安全和国家安全职业生涯提供了独特的实践培训机会。

This research program at the Nuclear Science Laboratory (NSL) of the University of Notre Dame addresses critical questions in nuclear astrophysics, nuclear structure physics, and nuclear physics applications. Low energy nuclear reaction measurements will be performed at the NSL accelerators using gamma and particle detection techniques to determine the reaction cross sections and reaction rates that determine the nucleosynthesis and timescales of quiescent and explosive stellar burning processes. The measurement of stellar reactions with low energy stable beams have cross section in the sub-nanobarn range and are mainly handicapped by cosmic and natural background radiation. The study of nuclear processes in stellar explosions relies on intense radioactive beams which will be provided by the Notre Dame TwinSol facility or other rare isotope accelerators in the US or Europe. New experimental methods and techniques will be developed by utilizing the new St George recoil separator, in connection with a new low-energy heavy ion accelerator, which is presently being installed. The nuclear structure program addresses the question of exotic rotational and vibrational excitation modes in nuclei which will help to better understand the fundamental characteristics of nuclear matter and investigate new modes of quantum phenomena predicted for nuclear few body systems. This program also incorporates measurements critical to many astrophysical phenomena, such as incompressibility of nuclear matter, which is important for our understanding of neutron stars; and mass measurements of nuclei important for various stellar processes and, especially, for understanding of the formation of heavy nuclei.The goal of the program is to investigate nuclear reactions which control the timescales, evolution, and the formation of elements in massive stars. Also studied will be reactions that drive stellar explosions such as novae and supernovae building the heavy elements from iron to lead. These studies will be coupled with computer simulations of the stellar environment to study the impact of these reactions on the observed elemental abundances in first generation and later generation stars. All these results will lead to a better understanding of the origin of the elements and the associated chemical history of our universe. For the astronomer, these results will lead to the identification of new observational signatures, such as neutrinos emitted from the core of stars, long-lived radioactive isotopes produced in supernova explosions, or gravitational waves emitted from the crust of exploding neutron stars. The program involves a large number of graduate and undergraduate students and provides a unique hands-on training opportunity for a career in nuclear physics, nuclear medicine, nuclear energy, radiation safety, and national security at US national laboratories, universities, medical facilities, and industries.