Exploring ${\hat{I}}^2$ decay and ${\hat{I}}^2$-delayed neutron emission in exotic ${}^{46,47}$Cl isotopes

Abstract

In this paper, $β^-$ and ${\hat{I}}^2$-delayed neutron decays of ${}^{46,47}$Cl are reported from an experiment carried out at the National Superconducting Cyclotron Laboratory using the Beta Counting System. The half-lives of both ${}^{46}$Cl and ${}^{47}$Cl were extracted. Based on the delayed ${\hat{I}}^3$-ray transitions observed, the level structure of $N=28$ ${}^{46}$Ar was determined. Completely different sets of excited states above the first $2^{+}$ state in ${}^{46}$Ar were populated in the ${}^{46}$Cl $\beta 0n$ and ${}^{47}$Cl $\beta 1n$ decay channels. Two new ${\hat{I}}^3$-ray transitions in ${}^{47}$Ar were identified from the very weak ${}^{47}$Cl $\beta 0n$ decay. Furthermore, ${}^{46}$Cl $\beta 1n$ and ${}^{47}$Cl $\beta 2n$ were also observed to yield different population patterns for levels in ${}^{45}$Ar, including states of different parities. The experimental results allow us to address some of the open questions related to the delayed neutron emission process. For isotopes with large neutron excess and high $Q_{\hat{I}}^2$ values, delayed neutron emission remains an important decay mode and can be utilized as a powerful spectroscopic tool. Experimental results were compared with shell-model calculations using the FSU and $V_{MU}$ effective interactions.