beta$ and $\beta$-delayed neutron decay of the $N=82$ nucleus $^{131}_{~49}$In$_{82}

• Main Authors: Dunlop, R, Svensson, C. E, Andreoiu, C, Ball, G. C, Bernier, N, Bidaman, H, Bildstein, V, Bowry, M, Cross, D. S, Dillmann, I, Dunlop, M. R, Garcia, F. H, Garnsworthy, A. B, Garrett, P. E, Hackman, G, Henderson, J, Measures, J, Mücher, D, Olaizola, B, Ortner, K, Park, J, Petrache, C. M, Pore, J. L, Smith, J. K, Southall, D, Ticu, M, Turko, J, Whitmore, K, Zidar, T
• Format: Journal Article
• Language: English
• Published: 28.03.2019
• Subjects: Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.1903.12277

The half-lives of three $\beta$ decaying states of $^{131}_{~49}$In$_{82}$ 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 $^{131}$In into $^{130}$Sn 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 $^{131}_{~49}$In$_{82}$ observed in this experiment. A significant expansion of the decay scheme of $^{131}$In, including 17 new excited states and 34 new $\gamma$-ray transitions in $^{131}_{~50}$Sn$_{81}$ is also reported. This leads to large changes in the deduced $\beta$ branching ratios to some of the low-lying states of $^{131}$Sn compared to previous work with implications for the strength of the first-forbidden $\beta$ transitions in the vicinity of doubly-magic $^{132}_{~50}$Sn$_{82}$.