In-Beam $\gamma$-Ray Spectroscopy of the N=50 Isotones on the Neutron-Rich Side
Résumé
High-spin states of $^{84}$Se, produced as a fission fragment in the fusion-fission reaction $^{18}$O+$^{208}$Pb and studied with the EUROBALL IV array, have been identified for the first time. Their interpretation gives new insights about the evolution of the N=50 shell gap at the vicinity of $^{78}$Ni. To characterize this evolution, it would be worth using a new device devoted to the high-spin studies of neutron-rich nuclei produced by asymetric fission modes. Such dedicated studies are reported in a second part.