Half-Lives of the Neutron-Rich N=82 Isotopes ¹³⁰Cd and ¹³¹In

Half-lives of N=82 nuclei below doubly-magic ¹³²Sn are key input parameters for calculations of any astrophysical r-process scenario and play an important role in the formation and shape of the second r-process abundance peak. In the past, shell-model calculations of neutron-rich nuclei near the N=82 neutron shell closure that are not yet experimentally accessible have been performed by adjusting the quenching of the Gamow-Teller (GT) operator to reproduce the half-life of ¹³⁰Cd [1]. The calculated half-lives of other nuclei in the region are known to be systematically too long. Recently, a shorter half-life for ¹³⁰Cd was reported [2,3]. A re-scaling of the GT quenching to reproduce this ¹³⁰Cd half-life resolved the discrepancy [2,3]. However, this created a new disagreement in the calculated half-life of ¹³¹In. This region is complicated due to the presence of isomers and β-n decays, making photopeak gating an ideal method to measure nuclear half-lives. In this talk, the half-lives of ¹³⁰Cd and ¹³¹In, as well as the spectroscopy of ¹³¹Sn measured with the GRIFFIN γ-ray spectrometer at TRIUMF will be presented.
[1] M. Hannawald et al., Nucl. Phys. A 688, 578 (2001)
[2] R. Dunlop et al., Phys. Rev. C 93, 062801(R) (2016)
[3] G. Lorusso et al., Phys. Rev. Lett. 114, 192501 (2015)