US-Belgium Cooperative Science: Nuclear Astrophysics with Radioactive and Isomeric Beams and Targets

该奖项将支持两组美国和比利时物理学家在核天体物理学方面的联合研究。美国小组将由乔治城大学的威廉·s·罗德尼博士指导。比利时合作者是比利时鲁汶核物理研究所的J. Vervier博士。这个项目的目标是执行一个实验程序，使用放射性光束来测量对理解核合成很重要的截面。在新星、超新星、x射线爆发以及可能在早期宇宙中，温度和密度使得一些放射性（和异构体）核素的寿命与它们被质子或α粒子诱导的核反应破坏的燃烧时间相当。在这些情况下，在发展恒星演化和核合成模型时必须考虑到这些反应。因此，使用放射性靶和（或）射线的可能性在核物理学界正日益受到重视。在这个项目中，概述的一系列实验代表了向提供所需截面信息的方向迈出的重要一步。鲁万-拉-纽夫耦合回旋加速器设备将能够产生进行这些实验所需的光束强度。美国目前还没有能够进行这种放射性光束测量的设施。这项研究将受益于罗德尼博士在核天体物理学方面的专业知识以及他的研究小组在积极的核实验方面的背景。这项研究的结果将有助于我们对恒星演化和恒星核合成的理解。

This award will support joint research in nuclear astrophy- sics between two groups of U.S. and Belgian physicists. The U.S. group will be under the direction of Dr. William S. Rodney, Georgetown University. The Belgium collaborator is Dr. J. Vervier, Institute for Nuclear Physics, Louvain, Belgium. The objective of this project is to carry out a program of experiments using radioactive beams to measure cross sections important to understanding nucleosynthesis. In novae, supernovae, X-ray bursters and possibly in the early universe, the temperature and density were such that the lifetimes of some radioactive (and isomeric) nuclides were comparable with the burning times for their destruction by proton- or alpha-particle-induced nuclear reactions. In these instances, these reactions must be taken into account in developing models for stellar evolution and nucleosyn- thesis. Thus, the potential for the use of radioactive targets and/or beams is receiving increasing attention in the nuclear physics community. In this project, the series of experiments outlined represent a major step in the direction of providing the needed cross section information. The Louvain-la-Neuve coupled cyclotron facility will be able to produce the required beam intensity to carry out these experiments. There are no existing U.S. facilities capable of such radioactive beam measurements. The research will benefit from Dr. Rodney's expertise in nuclear astrophysics and the background of his research group in active nuclear experimentation. The results of this research will contribute to our understanding of stellar evolution and nucleosynthesis in stars.