New data on excited states in very neutron rich nickel isotopes

The vicinity of $^{78}$Ni still remains elusive. Several experimental studies show evidence that $^{78}$Ni is a doubly magic nucleus, but deformed phenomena have been reported in this region. Spectroscopic studies around the region are of interest to clarify the shell evolution toward $^{78}$Ni. Beta decay studies of neutron-rich Co isotopes have been performed at the NSCL. The isotopes were produced in the fragmentation of the 140 MeV/u $^{82}$Se beam. These isotopes were implanted in a planar Germanium DSSD. The measurement of gamma-rays using clover detectors revealed excited states in neutron-rich Ni isotopes at high excitation energies. Preliminary results will be presented.