Nuclear Astrophysics With Heavy Ions

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The origin of the elements remains one of the most important questions in science today. Closely tied to this are questions of stellar burning and the characteristics of dense nuclear matter. This award will address these questions directly. Specifically, the two PIs and the students working with them will explore how heavy elements were formed in stellar environments, determine constraints on the characteristics of dense nuclear matter, and measure the fission barriers of exotic nuclei far from stability. The data collected will also help to resolve the discrepancies between theoretical calculations. The PIs will provide direct training to both undergraduate and graduate students in a wide range of skills and techniques, which will prepare the students for challenging and important careers in STEM fields. The central questions addressed by the proposed work are: (1) Does the r-process include a region of nuclear shape co-existence at N ~ 74? Measurement of nuclear masses near the r-process path is vital in understanding the systematics of r-process evolution, which is responsible for the production of nearly all nuclei heavier than iron. (2) What is the symmetry term of the nuclear equation-of-state at densities and asymmetries approaching those of neutron stars? This plays a vital role in the understanding of many aspects of neutron stars, such as their sizes, moments of inertia, cooling rates, and the thickness of their inner crusts. (3) What are the fission probabilities of nuclei near the termination of the r-process path? This question is critical in understanding the termination of the astrophysical r-process and constraining any fission cycling therein. Experiments to explore these questions have already been approved at the National Superconducting Cyclotron Laboratory.