BETA-DECAY OF NEUTRON-DEFICIENT EVEN-MASS INDIUM ISOTOPES - EVIDENCE FOR POPULATION OF HIGHLY-EXCITED STATES IN THE CADMIUM-DAUGHTER NUCLEI

By using mass-separated sources, positrons as well as beta-delayed protons and gamma-rays were measured from the beta-decay of In-102 (T1/2 22 +/- 1 s) and In-100 (T1/2 = 6.1 +/- 0.9 s). In particular, the average beta(+)/(beta(+) + EC) ratio for the decay of In-102 was measured to be 0.76(4) and the level scheme of Cd-102 was extended. Whereas no direct beta(+)/EC feeding of the identified Cd-102 levels was observed, there is evidence for population of Cd-102 states at high excitation energy followed by statistical gamma-decay. This feature, which has been deduced on the basis of the measured positron spectrum and the measured beta(+)/(beta(+) + EC) ratio of the In-102 decay, is compared to the decay properties of the heavier odd-odd indium isotopes In-104, In-106 and In-108, and is also used to interpret the observed P-delayed proton data of In-102 and In-100. For the first time, large-space shell-model calculations have been performed for the Gamow-Teller decay of heavy odd-odd nuclei. The decay results from these calculations are in good overall agreement with the gross decay properties of In-102 and In-100 deduced from the experiment.