Average decay properties in the quasi-continuum of 65Ni and neighbouring nuclei

Abstract

In this work, the average decay properties in the quasi-continuum of 65Ni have been studied. Both nuclear level density and gamma-strength function have been extracted for 65Ni and compared with data on 59Ni and 60Ni. The results for 65Ni have been discussed and related to the experimental observations in the nuclear level density and gamma-strength function of neighbouring nuclei. The experimental data on 65Ni were obtained at the Oslo Cyclotron Laboratory by bombarding a 99% enriched and 1 mg/cm^2 thick 64Ni foil with a 12.5 MeV deuteron beam. The reaction 64Ni (d,p) 65Ni was studied and the corresponding gamma-ray particle coincidences were measured. The resulting data on the excitation energy of 65Ni against the emitted gamma-rays were used to extract its nuclear level density and gamma-strength function by means of the Oslo method. The experimental level density of 65Ni is discussed and compared with the predictions given by the Constant Temperature Model. The observed structures are also interpreted as possibly related to the breaking of nucleon pairs. The structures observed in the gamma-strength function of 65Ni were described using several models for resonant gamma-decay and the corresponding parameters for these models were obtained. The results are interpreted and compared with the observed gamma-resonances in neighbouring nuclei.