Beta-decay half-lives of neutron rich Cu and Ni isotopes produced by thermal fission of235U and239Pu

The half-lives of very neutron rich isotopes of Ni and Cu have been measured. The isotopes are produced in very asymmetric thermal fission of235U and239Pu at the I.L.L. high flux reactor. They are separated by means of the Lohengrin spectrometer. They are identified with aΔE-E ionization chamber and implanted in one of the 8 Si planar detectors where theβ-particles are also detected. The time correlations between the implantation and the detection ofβ-particles provide the half-life. The values obtained are compared to current theoretical predictions.