Low-energy structure of 61Mn populated following $\beta$ decay of 61Cr

TL;DR

This study investigates the beta decay of $^{61}$Cr to understand the low-energy structure of $^{61}$Mn, revealing a new half-life, gamma-ray assignments, and structural similarities with lighter Mn isotopes, indicating systematic nuclear behavior.

Contribution

The paper provides the first detailed low-energy level scheme of $^{61}$Mn following $^{61}$Cr decay, including a new half-life measurement and gamma-ray assignments, highlighting systematic trends in Mn isotopes.

Findings

New half-life of 233 ms for $^{61}$Cr

Seven gamma rays assigned to $^{61}$Mn

Structural similarity with lighter Mn isotopes

Abstract

$\beta$ decay of the $^{61}$Cr$_{37}$ ground state has been studied. A new half-life of 233 +/- 11 ms has been deduced, and seven delayed $\gamma$ rays have been assigned to the daughter, $^{61}$Mn$_{36}$. The low-energy level structure of $^{61}$Mn$_{36}$ is similar to that of the less neutron-rich $^{57,59}$Mn nuclei. The odd-A $_{25}$Mn isotopes follow the systematic trend in the yrast states of the even-even, Z + 1 $_{26}$Fe isotopes, and not that of the Z - 1 $_{24}$Cr isotopes, where a possible onset of collectivity has been suggested to occur already at N = 36.