The isotopes 68 74 Ni, of interest both for nuclear physics and astrophysics, have been produced in proton-induced fission of 238 U and ionized in a laser ion guide coupled to an on-line mass separator. Their b decay was studied by means of b-g and g-g spectroscopy. Half-lives have been determined and production cross sections extracted. A partial level scheme is presented for 73 Cu and additional levels for 71 Cu, providing evidence for a sharply lowered position of the p1f 5͞2 orbital as occupancy of the n1g 9͞2 state increases. The latter may have a clear impact on the predicted structure and decay properties of doubly magic 78 Ni. [S0031-9007 (98)07340-2]

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A β-decay study of the even mass 74,76,78 Cu isotopes toward levels in 74,76,78 Zn was performed at the ISOLDE mass separator. The copper isotopes were produced in proton-or neutron-induced fission reactions on 238 U, 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.

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Using resonant laser ionization, beta-decay studies, and for the first time mass measurements, three beta-decaying states have been unambiguously identified in 70Cu. A mass excess of -62 976.1(1.6) keV and a half-life of 44.5(2) s for the (6-) ground state have been determined. The level energies of the (3-) isomer at 101.1(3) keV with T(1/2)=33(2) s and the 1+ isomer at 242.4(3) keV with T(1/2)=6.6(2) s are confirmed by high-precision mass measurements. The low-lying levels of 70Cu populated in the decay of 70Ni and in transfer reactions compare well with large-scale shell-model calculations, and the wave functions appear to be dominated by one proton-one neutron configurations outside the closed Z=28 shell and N=40 subshell. This does not apply to the 1+ state at 1980 keV which exhibits a particular feeding and deexcitation pattern not reproduced by the shell-model calculations.