Probing nuclear structures in the vicinity of78Ni withβ- andβn-decay spectroscopy of84Ga

The decay of ${}^{84}$Ga has been reinvestigated at the PARRNe online mass separator of the electron-driven installation ALTO at IPN Orsay. The nominal primary electron beam of 10 $\ensuremath{\mu}$A (50 MeV) on a ${}^{238}$UC${}_{x}$ target in combination with resonant laser ionization were used for the first time at ALTO. Improved level schemes of the neutron-rich ${}^{83,84}$Ge ($Z=32$) isotopes were obtained. The experimental results are compared with the state-of-the-art shell model calculations and discussed in terms of collectivity development in the natural valence space outside the ${}^{78}$Ni core.