We report on the first β-decay data of Sb138 to Te138 isotopes beyond the doubly magic Sn132. The parent nucleus was produced by the in-flight fission of a U238 beam on a Be9 target at 345 MeV per nucleon and measured at the BigRIPS separator of the Radioactive Isotope Beam Factory at RIKEN. By using advanced β-γ spectroscopy techniques, the half-life and the tentative spin-parity of Sb138 were measured to be 346(19) ms and (3-), respectively. In addition, we observed several low-lying non-yrast states in Te138 for the first time. Our data allowed us to rearrange the positions of the first 2+ and 4+ states in this nucleus and to construct the level scheme of Te138 in accordance with shell-model calculations. Additionally, we extend energy systematics of Te isotopes within neutron numbers 54 and 86.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics