129Sn and 129Sb beta decays

Abstract

Samples of 129Sn and 129Sb were obtained by on-line mass-separation techniques applied to 235U thermal-fission products. Half-lives of (6.9±0.1) and (2.5±0.1) min have been measured for the 129Sn beta decays. Decay schemes are proposed based on gamma-ray energies and intensities and gamma-gamma coincidence results. A new half-life of (17.7±0.1) min, besides the well known 4.4 h one, was observed in the 129Sb decay. A level scheme fed by this decay is proposed taking into account our results and previously reported nuclear reactions data. The 129Sb structure is compared with a particle-core coupling calculation.