Nuclear Structure and Nuclear Astrophysics

核结构与核天体物理学

• 批准号: 1068192
• 负责人: Michael Wiescher
• 金额: $ 591.6万
• 依托单位: University of Notre Dame
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1068192&HistoricalAwards=false
• 关键词: Nuclear; Structure; Astrophysics

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.

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学，核结构物理学和核物理应用中的关键问题。低能核反应测量将在NSL加速器上使用伽马和粒子探测技术进行，以确定反应截面和反应速率，从而确定静止和爆炸恒星燃烧过程的核合成和时间尺度。用低能稳定束流测量恒星反应的截面在亚纳米量级，主要受到宇宙和自然背景辐射的限制。研究恒星爆炸中的核过程依赖于强烈的放射性束，这些束将由美国或欧洲的Notre Dame TwinSol设施或其他罕见的同位素加速器提供。将利用新的St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，开发新的实验方法和技术。核结构计划解决了原子核中奇异的旋转和振动激发模式的问题，这将有助于更好地理解核物质的基本特征，并研究预测为核少体系统的量子现象的新模式。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，这对我们了解中子星很重要;和质量的测量对于各种恒星过程，特别是对于理解重核的形成是重要的。该计划的目标是研究控制时间尺度，演化，以及大质量恒星中元素的形成 还将研究驱动恒星爆炸的反应，如新星和超新星，建造从铁到铅的重元素。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后来一代恒星中观测到的元素丰度的影响。所有这些结果将有助于我们更好地理解元素的起源和我们宇宙的相关化学历史。 对于天文学家来说，这些结果将导致识别新的观测特征，例如从恒星核心发射的中微子，超新星爆炸中产生的长寿命放射性同位素，或从爆炸中子星地壳发射的引力波。该计划涉及大量的研究生和本科生，并为美国国家实验室，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提供了独特的实践培训机会。