The 3701 keV Neutron g9/2 Single-particle State in 57Ni

The neutron g(9/2) single-particle state in Ni-57 has been unambiguously identified in a combined measurement of the linear polarization, angular distribution, and angular correlation of gamma rays following the fusion-evaporation reaction Si-28(S-32,2pn)Ni-57 at a beam energy of 90 MeV. The linear polarization was measured with a EUROBALL cluster detector and a prototype of an encapsulated six-fold segmented hexaconical Ge-detector. The spin of the 3701 keV level in Ni-57 was confirmed to be I = 9/2 and its parity determined to be positive.