L. Frankland

Shell-model calculations near N=Z=28

A shell-model truncation which has been shown to be useful in the region is applied to several nuclei above and below Z = 28. Comparisions of energy levels with known data suggest the truncation will be useful for workers investigating new data in this region. High-spin isomers are predicted in and .

Half-Lives of the Odd-Odd N = Z Nuclei

The heavy odd-odd nuclei , , , have been produced at GANIL by fragmentation of a beam on a natural nickel target. The species of interest were selected and identified by their energy loss in a silicon detector and their time of flight through the LISE spectrometer. The ions were implanted in a silicon strip detector in which their -decay was observed. The measured half-lives for , , correspond to superallowed transitions and may sign Fermi transitions on the basis of values. Our experimental results pave the way for further and more precise measurements of these nuclei.

^78

The study of the β decay of some N=Z nuclei in the A=70 mass range have been performed using the GANIL and CERN/ISOLDE facilities. The fast decays of three Tz=0 odd-odd nuclei have been measured for the first time which extend the number of superallowed transitions. Information has been obtained on the Gamow Teller strength distribution in the β+-EC decay of two even-even N=Z isotopes 76Sr and 72Kr. Results are compared with theoretical predictions giving indication about the shape of the ground state of the parent nucleus.

Y,

The heavy odd-odd N=Z nuclei {sup 78}Y,{sup 82}Nb,{sup 86}Tc have been produced at GANIL by fragmentation of a 60 MeV/u {sup 92}Mo beam on a natural nickel target. Their lifetime have been measured for the first time, using the identification-implantation and subsequent time correlated {beta} counting technique at the LISE spectrometer. The obtained half-lives for {sup 78}Y,{sup 82}Nb,{sup 86}Tc are consistent with the microscopic predictions. These nuclei are good candidates to extend the mass range for the V{sub ud} matrix element evaluation and our experimental results highlight the interest of further investigation of their excited states and {beta} decay schemes as a function of isospin. {copyright} {ital 1998 American Institute of Physics.}

^82

The heavy odd-odd N=Z nuclei {sup 78}Y,{sup 82}Nb,{sup 86}Tc have been produced at GANIL by fragmentation of a 60 MeV/u {sup 92}Mo beam on a natural nickel target. Their lifetime have been measured for the first time, using the identification-implantation and subsequent time correlated {beta} counting technique at the LISE spectrometer. The obtained half-lives for {sup 78}Y,{sup 82}Nb,{sup 86}Tc are consistent with the microscopic predictions. These nuclei are good candidates to extend the mass range for the V{sub ud} matrix element evaluation and our experimental results highlight the interest of further investigation of their excited states and {beta} decay schemes as a function of isospin. {copyright} {ital 1998 American Institute of Physics.}