Structure of129Ba from the decay of129La
The structure of129Ba is investigated through the beta decay of129La, whose half-life is measured to be 11.6±0.2 m. The decay properties are studied by means of beta, gamma and conversion electron spectroscopy techniques. Many transitions are observed and a level scheme of129Ba with deduced129Ba values is proposed. The total decay energy of129Ba is measured to be 3.72±0.05 MeV, which is compared with predictions of mass formulae. Low-lying structure of129Ba is discussed in terms of collective models.