Precision measurements of proton emission from the ground states of Ta156 and Re160

The decays of the πd_3/2 ground states of Ta156 and Re160 have been studied in detail using the GREAT spectrometer. More than 7000 Re160 nuclei were produced in reactions of 290- and 300-MeV Ni58 ions with an isotopically enriched Cd106 target and separated in flight using the RITU separator. The proton and α decays of the πd_3/2 level were confirmed and the half-life and branching ratios of this state were determined with improved precision to be t_1/2=611±7 μs and b_p=89±1% and b_α=11±1%, respectively. The α-decay branch populated the ground state of Ta156, allowing improved values for the proton-decay energy and half-life to be obtained (E_p=1011±5 keV; t_1/2=106±4 ms). The β decay of this level was identified for the first time and a branching ratio of b_β=29±3% was deduced. The spectroscopic factors deduced from these measurements are compared with predictions.