Advances in Radioactive Isotope Science

Decay Spectroscopy of Neutron-Rich Cd Around the \mbox{\textit{N} = 82} Shell Closure

1 Jun 2017, 17:50

15m

Longs Peak

Invited Presentation Breakout 1

Speaker

Nikita Bernier (TRIUMF/UBC)

Description

The neutron-rich Cadmium isotopes around $A=130$ are of special interest to both nuclear structure and astrophysics. Situated near the well-known magic numbers at $Z=50$ and $N=82$, these nuclei are prime candidates to study the evolving shell structure observed in exotic nuclei. Additionally, the extra binding energy observed around the nearby doubly-magic $^{132}$Sn has direct correlations in astrophysical models, leading to the second r-process abundance peak at $A\approx130$ and the corresponding waiting-point nuclei around $N=82$. The $\beta$-decay of the $N=82$ isotope $^{130}$Cd into $^{130}$In was first studied a decade ago [1], but the information for states of the lighter indium isotope ($^{128}$In) is still limited. These motivating factors has led us to perform detailed $\gamma$-ray spectroscopy following the $\beta$-decay of $^{128-132}$Cd using the GRIFFIN [2] facility at TRIUMF, which is capable of performing spectroscopy down to rates of \mbox{0.1 pps}. The ongoing analysis of the $^{128,131,132}$Cd will be presented. Already in $^{128}$Cd, 23 new transitions and 15 new states have been observed in addition to the 4 previously observed excited states [3]. Its half-life has also been remeasured via the time distribution of the strongest $\gamma$-rays in the decay scheme with a higher precision [4]. For $^{131}$Cd, results will be compared with the recent EURICA data. These data highlight the unique capabilities of GRIFFIN for decay spectroscopy on the most exotic, short-lived isotopes, and the necessity to re-investigate also "well-known" decay schemes for missing transitions. References: [1] I. Dillmann {\it et al}, Phys. Rev. Let. {\bf 91}, 162503 (2003) \h\ [2] C.E. Svensson and A.B. Garnsworthy, Hyperfine Int. {\bf 225}, 127 (2014) \\ [3] B. Fogelberg, Proc. Intern. Conf. Nuclear Data for Science and Technology, Mito, Japan, p.837 (1988) \\ [4] R. Dunlop {\it et al}, Phys. Rev. C {\bf 93}, 062801(R) (2016).