Beta decay studies around doubly magic 78Ni

The main motivations to study very neutron rich nuclei in the $^ {78}$Ni region are related to the evolution of nuclear structure and to the path of nucleosynthesis within rapid neutron capture. In particular, neutrons filling g$_{9/2}$ orbital between $^{68}$Ni and $^{78}$Ni affect spin-orbit splitting of proton single-particle states. An increasing beta- delayed neutron emission probabilities are changing the isobaric distributions of nuclei involved in the r-process. The report on the recent results on the decay of most neutron- rich isotopes of copper and gallium [1] will be presented. These proton-induced $^{238}$U fission products were produced and studied at Holifield Radioactive Ion Beam Facility at Oak Ridge using a ``ranging-out'' method [2] for postaccelerated beams purification. In collaboration with Jeff Winger and Sergey Iliushkin, Mississippi State University; Carl Gross and Dan Shapira, ORNL; Carrol Bingham, UTK; Robert Grzywacz, ORNL; Chiara Mazzocchi, Sean Liddick, Steven Padgett, and Mustafa Rajabali, UTK; Jon Batchelder, UNIRIB-ORAU; Edward Zganjar and Andreas Piechaczek, LSU; Christopher Goodin and Joseph Hamilton, Vanderbilt University; and Wojciech Krolas, JIHIR Oak Ridge.\newline [1] J. Winger et al., contr. to INPC, Japan, June 2007\newline [2] C.J. Gross et al., EPJ A 25, s01, 115 (2005)