Christopher Borgmann

Probing the N = 32 Shell Closure below the Magic Proton Number Z = 20: Mass Measurements of the Exotic Isotopes52,53K

The recently confirmed neutron-shell closure at N=32 has been investigated for the first time below the magic proton number Z=20 with mass measurements of the exotic isotopes (52,53)K, the latter being the shortest-lived nuclide investigated at the online mass spectrometer ISOLTRAP. The resulting two-neutron separation energies reveal a 3 MeV shell gap at N=32, slightly lower than for 52Ca, highlighting the doubly magic nature of this nuclide. Skyrme-Hartree-Fock-Bogoliubov and ab initio Gorkov-Green function calculations are challenged by the new measurements but reproduce qualitatively the observed shell effect.

Neutron Drip-Line Topography

The development of microscopic mass models is a crucial ingredient for the understanding of how most of the elements of our world were fabricated. Confidence in drip‐line predictions of such models requires their comparison with new mass data for nuclides far from stability. We combine theory and experiment using results that are state of the art: the latest mass measurements from the Penning‐trap spectrometer ISOLTRAP at CERN‐ISOLDE are used to confront the predictions of the latest Skyrme‐Hartree‐Fock‐Bogoliubov (HFB) microscopic mass models. In addition, we compare the new data to predictions of other types of mass models and the extrapolative behavior of the various models is analyzed to highlight topographical trends along the shores of the nuclear chart.