EAPSI: Measurements of Collective Vibrations of Exotic Nuclei using Radioactive Ion Beams

Howard Kevin B, Notre Dame IN

Investigators

Abstract

The Rare Isotope Beam Facility (RIBF) at RIKEN in Japan is one of the leading institutes for studying the properties of nuclei which quickly undergo decay. This award will support the study of bulk properties of the tin nucleus which, for example, undergoes substantial radioactive decay within a minute of its production. RIBF is extremely well-suited to measure these properties. These measured values will then serve to aid other researchers in formulating and better constraining models to describe the conditions under which a given nucleus may form, exist, and if applicable, subsequently undergo radioactive decay. This fundamental understanding is of great importance in several applications, not limited to: the application of heavy-ion therapy for nuclear medicine in cancer treatments; developing methods for the appropriate disposal of radioactive waste; and further improving the domestic profile of clean and safe nuclear energy infrastructure. The research will take place under the mentorship of Dr. Tomohiro Uesaka, Chief Scientist at the Spin-Isospin Lab at the RIKEN Nishina Center for Accelerator-Based Science. The nucleus being investigated (tin-132, an isotope of tin with atomic mass of 132 units) is highly asymmetric in proton and neutron numbers and as a result, has great effect in constraining the asymmetry component of the nuclear incompressibility in the nuclear Equation of State (EoS) and determining the symmetry energy. The EoS is the fundamental description of bulk nuclear properties, and the incompressibility of nuclear matter represents the amount of energy required to change the density of nuclear matter from its equilibrium value. At RIBF, an experiment on tin-132 has been performed in Spring 2016, and this award will support the on-site extraction and analysis of the data, as well as optimization of the time projection chamber to further probe the nuclei in this region. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.