Properties of low-lying states in $^{65}$Co from lifetime measurements
Résumé
The low-energy structure of Co65 was studied by means of γ- and fast-timing spectroscopy at the ISOLDE/CERN facility. The known level scheme of Co65 populated following the β− decay of Fe65 was expanded. The experimental results were compared with large-scale shell-model calculations. The measured long lifetime of the (1/21−) level confirms its nature as a highly collective state with proton excitations across the Z=28 gap and neutrons across the N=40 subshell.