Beta decay of 100In

The β decay of 100In, the one proton hole and one neutron particle neighbor to 100Sn, was investigated at the GSI on-line mass separator by using germanium detectors and a NaI total-absorption spectrometer. On the basis of βγγ coincidences, the 100In decay scheme was established for the first time. The ground-state spin and parity for 100In are discussed by investigating β feeding of levels in 100Cd and β-delayed proton emission to 99Ag. The half-life was remeasured and found to be 5.9(2) s. The QEC value was determined from the measured EC/β+ ratio for the β-delayed protons to be 10.08(23) MeV. The main fraction of the β feeding was established to populate the region of 6 MeV excitation energy, which corresponds to a total Gamow-Teller (GT) strength of 3.9(9) and a centroid at 6.4 MeV. Large-scale shell-model calculations employing a realistic interaction are used to assign configurations to states in 100In and 100Cd. The GT β-decay strength distribution measured in the total absorption experiment is compared to shell-model predictions. The deduced overall hindrance of the GT strength agrees with the values predicted for the 100Sn GT decay. (orig.)