Revisiting the decay scheme and half-life of

The decay of 139Ba to levels of 139La has been studied employing singles and $ \gamma$ -$ \gamma$ coincidence spectroscopy techniques, using four Compton suppressed Clover detectors. The $ \gamma$ -$ \gamma$ coincidence data obtained in the present work has been more conclusive as compared to the coincidence data obtained using NaI(Tl)-Ge(Li) detectors in the earlier investigations. The relative intensities of twenty-seven $ \gamma$ -ray transitions have been determined. The $ \gamma$ -ray transitions with energies 1044 and 1525keV, attributed to the decay of 139Ba in the previous works, have been found to be due to long-lived impurities. The 1691keV transition, previously assigned to the decay of 139Ba , is found to be mainly associated with an impurity with only a small fraction belonging to 139Ba decay. The half-life of 139Ba has been measured. The present work attempts to resolve some of the discrepancies in the previous investigations, which will be helpful in the precise determination of $ \beta$ -decay scheme of 139Ba