Evolution of the nuclear structure approaching 78 Ni : β decay of 74 − 78 Cu

A β-decay study of the even mass 74,76,78Cu isotopes toward levels in 74,76,78Zn was performed at the ISOLDE mass separator. The copper isotopes were produced in protonor neutron-induced fission reactions on 238U, laser ionized, mass separated, and sent to a β-γ detection system. Half-lives, decay schemes, and possible spin configurations were obtained for the copper isotopes. The results are compared with calculations using schematic forces as well as large-scale shell-model calculations with realistic forces.