New excited states in Ge-82:possible weakening of the N=50 closed shell

Excited states in Ge-82, populated in the spontaneous fission of Cm-248, have been studied by means of prompt gamma spectroscopy, using the EUROGAM2 multidetector array. The known level at 2287 keV is assigned spin and parity 4(+). Two new excited levels in Ge-82, with spins and parities 5,6(+), are proposed at 2930 and 3228 keV. At least one of the new levels is expected to be be due to neutron excitations across the N=50 shell gap. Its low energy, as compared to heavier N=50 isotones, supports the suggestion of other works that the N=50 shell closure is weakening when approaching the expected double shell closure at Ni-78.

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