Beta Decay Of 72Co And Excited Levels In 72Ni

An experiment was performed at GANIL to observe isomeric‐ and beta‐delayed gamma rays from very neutron‐rich nuclei around 74Ni. Fragmentation products of the 86Kr beam at 58 AMeV were studied using new devices: the LISE 2000 spectrometer and detectors from the EXOGAM germanium array. The primary aim of the experiment was to find the 8+ microsecond isomer in 76Ni and to perform beta decay spectroscopy of Co nuclei. We have successfully measured the beta delayed gammas from the decay of 72Co to 72Ni. The energies for the lowest excited states in 72Ni are proposed, with the first 2+ state at 1096 keV. These findings suggest a solution of the problem of the disappearance of the 8+ isomer in 72Ni. We also measured beta decay of other neutron‐rich Co isotopes including 70Co. First evidence was found for a new short lived isomer, most likely the Iπ=8+ state, in 76Ni.