Study of $N=50$ gap evolution around $Z=32$: new structure information for ${}^{82}$Ge

Abstract

Medium spin states of light N = 50 isotones have been populated using fast neutron-induced fission of ${}^{232}$Th. Online prompt $\gamma$ spectroscopy has been performed using the hybrid $\gamma$ spectrometer $\nu \text {-}$Ball coupled to the LICORNE directional neutron source at the ALTO facility of IJCLab. Medium spin states of the neutron-rich nucleus ${}^{82}$Ge have been investigated using $\gamma$-$\gamma$ and $\gamma$-$\gamma$-$\gamma$ coincidence data to exploit the resolving power of $\nu \text {-}$Ball. Two new transitions were assigned to this nucleus and a new level was placed in the level scheme. We tentatively assigned to this new state a ($7^{+}$) spin-parity, which is interpreted as a new $N=50$ core breaking state. This provides further insight into the energy evolution of the $N=50$ shell gap toward ${}^{78}$Ni.