Abstract
High-precision mass measurements of more than 30 neutron-rich nuclides around the closed proton shell were performed with the triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN to address the question of a possible neutron shell closure at . The results for (), (), and () have a relative uncertainty of the order of . In particular, the mass of was measured for the first time. We analyze the resulting mass surface for signs of magicity, comparing the behavior of with that of known magic numbers and with midshell behavior. While the classic indications from the mass surface show no evidence for a shell closure at , there is evidence for a weak—and very localized—effect for , consistent with findings from nuclear spectroscopy studies.
5 More- Received 14 December 2006
DOI:https://doi.org/10.1103/PhysRevC.75.044303
©2007 American Physical Society