[en] 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 T_z=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

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

[en] The heavy odd-odd N=Z nuclei ⁷⁴Rb, ⁷⁸Y, ⁸²Nb, ⁸⁶Tc have been produced at GANIL by fragmentation of a 60 MeV/u ⁹²Mo 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 β-decay was observed. The measured half-lives for ⁷⁸Y, ⁸²Nb, ⁸⁶Tc correspond to superallowed transitions and may sign Fermi transitions on the basis of log ft values. Our experimental results pave the way for further and more precise measurements of these nuclei. (author)