Recent advances in generating beams of radioactive ions (RIBs) have altered our perception of the atomic nucleus. Familiar interpretations of experimental observables, such as the shell structure of stable nuclei, have been seen to evolve dramatically as one moves into ‘exotic’ regions of the nuclear landscape. Such models continue to be challenged as beam intensities improve and commensurate detector systems are developed. The CARIBU upgrade to the ATLAS facility at Argonne National Laboratory, USA is one such example. CARIBU exploits heavyactinide spontaneous fission in generating beams of neutron-rich exotic nuclei. This offers exciting prospects for investigation into nuclear structure far from stability, origins of the elements through the rapid neutron-capture process in stars, and applied topics such as the reactor antineutrino anomaly and decay heat discrepancies.
In this talk, I will give an overview of how detailed studies of single-nucleon quantum orbitals have shaped our understanding of the forces at play within atomic nuclei. This will include their dynamic evolution across isotopic chains, the emergence of new shell closures and how measurement of their occupancies may help to elucidate the absolute neutrino mass scale. I will also describe recent progress with RIB experiments, including first results of nuclear structure studies at the CARIBU facility and possibilities that will be pursued in the near future.
Dr AJ Mitchell was awarded a Ph.D. in Nuclear Physics from the University of Manchester (UK) in 2012. His doctoral research focused on evolving single-particle structures within atomic nuclei and their relevance to the strong nuclear force and exotic decay processes, such as neutrinoless double-beta decay. After graduating, he took up a postdoctoral research position at the University of Massachusetts Lowell (USA). During this time, he began his work with radioactive ion-beams, using beta-decay of neutron-rich exotic nuclei to probe aspects of nuclear structure, stellar nucleosynthesis and nuclear applications. AJ joined ANU’s Department of Nuclear Physics in 2015, where he continues to explore the structure of nuclei both near and far from stability.