Experimental study of β and β-n decay of the neutron-rich N=54 isotone As 87

The β-decay properties of neutron-rich As87 produced in the proton-induced fission of U238 were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The low-energy excited states in N=53 Se87 and N=52 Se86 were identified through β-γ and β-delayed neutron-γ decay of As87, respectively. The experimental systematics of low-energy levels of N=53 isotones, Z=34 Se,87 and Z=32 Ge85, and along with an analysis of shell-model calculations, allow us to discuss the main features of excited states expected for the next N=53 isotone, Zn83.