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

TL;DR

This study investigates the beta decay and neutron emission of exotic chlorine isotopes $^{46,47}$Cl, revealing new excited states and decay patterns, and compares experimental data with shell-model calculations to enhance understanding of neutron-rich nuclei.

Contribution

It provides new experimental data on the decay properties and level structures of $^{46,47}$Cl, including the first identification of certain gamma-ray transitions and population patterns in daughter nuclei.

Findings

Different excited states populated in decay channels

Identification of new gamma-ray transitions in $^{47}$Ar

Observed decay patterns in $^{45}$Ar levels

Abstract

In this paper, $\beta^-$ and $\beta$-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 $\gamma$-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 $\beta0n$ and $^{47}$Cl $\beta1n$ decay channels. Two new $\gamma$-ray transitions in $^{47}$Ar were identified from the very weak $^{47}$Cl $\beta0n$ decay. Furthermore, $^{46}$Cl $\beta1n$ and $^{47}$Cl $\beta2n$ 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 $Q_{\beta}$ 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.