Study of the N = 50 major shell effect toward ⁷⁸Ni at PARRNe^⋆

The gamma-ray de-excitations following the beta-decay of Ga-83 and the beta-n decay of Ga-84 have been studied. The radioactive species were produced using the PARRNe on-line mass-separator installed at the IPN Orsay Tandem accelerator. Two gamma-lines were attributed to Ge-83 with the aid of beta-gamma and gamma-gamma coincidences. The Z identification of the gamma-lines was provided by time analysis of a buid-up/decay cycle. The excited levels of Ge-83 can be explained by the coupling of the single neutron state nu 2d(5/2) to the first 2(+) excitation of the Ge-82 core.