g factor measurements of µs isomeric states in neutron-rich nuclei around 68 Ni produced in projectile-fragmentation reactions

Abstract We report the first g factor measurement on microsecond isomers of neutronrich nuclei produced in projectile-fragmentation reactions at intermediate energies. The nuclides in the vicinity of 68 Ni were produced and spin oriented following the fragmentation of a 76 Ge, 61.4 MeV u −1 beam at GANIL. The LISE spectrometer was used to select the nuclei of interest. The time-dependent perturbed angular distribution (TDPAD) method was applied in combination with the heavy-ion-gamma correlation technique to measure the g factors of 69m Cu (J π = 13/2 + , T 1/2 = 350 ns) and 67m Ni (J π = 9/2 + , T 1/2 = 13.3 µs). Specific details of the experimental technique and the comparison of the results (|g( 69m Cu)| = 0.225(25) and |g( 67m Ni)| = 0.125(6)) with theoretical calculations are discussed. These results provide another indication of the importance of proton excitations across the Z = 28 shell gap