Structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Co</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>65</mml:mn><mml:mo>,</mml:mo><mml:mn>67</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>studied through the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>β</mml:mi></mml:mrow></mml:math>decay of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Fe</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>65</mml:mn><mml:mo>,</mml:mo><mml:mn>67</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>and a deep-inelastic reaction
Abstract
The neutron-rich isotopes $^{65,67}\mathrm{Fe}$ and $^{65}\mathrm{Co}$ have been produced at the LISOL facility, Louvain-La-Neuve, in the proton-induced fission of $^{238}\mathrm{U}$. Beams of these isotopes have been extracted with high selectivity by means of resonant laser ionization combined with mass separation. Yrast and near-yrast levels of $^{65}\mathrm{Co}$ have also been populated in the $^{64}\mathrm{Ni}+^{238}\mathrm{U}$ reaction at Argonne National Laboratory. The level structure of $^{65}\mathrm{Co}$ could be investigated by combining all the information from both the $^{65}\mathrm{Fe}$ and $^{65}\mathrm{Co}\ensuremath{\beta}$ decay and the deep-inelastic reaction. The $^{65}\mathrm{Fe}$, $^{65}\mathrm{Co}$, and $^{67}\mathrm{Fe}$ decay schemes and the $^{65}\mathrm{Co}$ yrast structure are fully established. The $^{65,67}\mathrm{Co}$ level structures can be interpreted as resulting from the coexistence of core-coupled states with levels based on a low-energy proton-intruder configuration.