Investigating the strength of the N = 34 subshell closure in 54Ca

Abstract

Excited states in the exotic N = 34 isotope 54Ca have been measured for the first time via in-beam γ-ray spectroscopy with proton-knockout reactions from 55Sc and 56Ti radioactive beams on a Be reaction target at the Radioactive Isotope Beam Factory, Japan. A strong candidate for the transition from the first 2+ state to the 0+ ground state has been identified, in addition to several other weaker transitions. The structure of the N = 33 isotope 53Ca has also been investigated from the same data. Preliminary γ-ray energy spectra for 54Ca and 53Ca will be presented and the significance of the N = 34 subshell closure will be examined. Predictions of several shell-model interactions performed in the fp model space will be discussed in light of the new results.