Analysis of alpha-induced reactions on $^{151}$Eu below the Coulomb barrier

TL;DR

This study presents new measurements of alpha-induced reaction cross sections on $^{151}$Eu near the Coulomb barrier, refining optical model parameters and analyzing nuclear structure implications.

Contribution

It provides novel experimental data and supports updated alpha optical model potentials below the Coulomb barrier, including a tentative spin-parity assignment for an isomer in $^{154}$Tb.

Findings

Supported recent alpha optical potential parameters

Refined statistical model analysis of reaction cross sections

Proposed a new spin-parity for $^{154}$Tb isomer

Abstract

Novel measurements of $(\alpha,\gamma)$ and $(\alpha$,n) reaction cross sections on the target nucleus $^{151}$Eu, close to the reaction thresholds, support the setting up of recent parameters of the $\alpha$-particle optical model potential below the Coulomb barrier. A better understanding of the $\alpha$-particle optical potential at these energies leads to a statistical model analysis of additional partial cross sections that were formerly measured but not considered within the model analysis. On this basis we have tentatively assigned a modified $J^{\pi}$=9$^-$ spin and parity to the 22.7-h isomer in $^{154}$Tb.