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

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.