Half-Lives of Neutron Rich ${}^{130}$Cd and ${}^{131}$In

Abstract

The half-lives of isotopes around the $N=82$ shell closure are an important ingredient in astrophysical simulations and strongly influence the magnitude of the second $r$-process abundance peak in the $A\sim 130$ region. The most neutron-rich $N=82$ nuclei are not accessible to the current generation of radioactive beam facilities and $r$-process simulations must therefore rely on calculations of the half-lives of the isotopes involved. Half-life measurements of the experimentally accessible nuclei in this region are important in order to benchmark these calculations. The half-life of ${}^{130}$Cd is particularly important as it is used to tune the Gamow-Teller quenching in shell-model calculations for the ${\hat{I}}^2$ decay of other nuclei in this region. In this work, the GRIFFIN ${\hat{I}}^3$-ray spectrometer at the TRIUMF-ISAC facility was used to measure the half-life of ${}_{48}^{130}$Cd${}_{82}$ to be $T_{1/2}=126(4)$ ms. In addition, the half-lives of the three ${\hat{I}}^2$ decaying states of ${}_{49}^{131}$In${}_{82}$ were measured to be $T_{1/2}(1/2^{-})=328(15)$ ms, $T_{1/2}(9/2^{+})=265(8)$ ms, and $T_{1/2}(21/2^{+})=323(50)$ ms, respectively, providing an important benchmark for half-life calculations in this region.

Talk presented CIPANP2018. 9 pages, LaTeX, 5 pdf figures, 1 png figure