β decay and β-delayed neutron decay of the N=82 nucleus 13149In82

The half-lives of three j-decaying states of In-131(49)82 have been measured with the GRIFFIN gamma-ray spectrometer at the TRIUMF-ISAC facility to be T-1/2(1/2(-)) = 328(15)ms, T-1/2(9/2(+)) = 265(8)ms, and T-1/2(21/2(+)) = 323(55)ms, respectively. The first observation of gamma rays following the beta n decay of In-131 into Sn-130 is reported. The beta-delayed neutron emission probability is determined to be P-1n = 12(7)% for the 21/2(+) state and 2.3(3)% from the combined 1/2(-) and 9/2(+) states of In-131(49)82 observed in this experiment. A significant expansion of the decay scheme of In-131 including 17 new excited states and 35 new gamma-ray transitions in Sn-131(50)81 is also reported. This leads to large changes in the deduced beta-branching ratios to some of the low-lying states of Sn-131 compared to previous work with implications for the strength of the first-forbidden beta transitions in the vicinity of doubly magic Sn-132(50)82.