# Nuclear level densities and gamma-ray strength functions of $^{180,181,182}$Ta

## TL;DR

This study measures nuclear level densities and gamma-ray strength functions of tantalum isotopes using particle-$\gamma$ coincidence experiments, providing insights into nuclear structure and reactions relevant for nuclear physics applications.

## Contribution

It presents new experimental data on NLDs and $\gamma$SFs of $^{180,181,182}$Ta and analyzes the scissors resonance splitting, suggesting triaxial deformation in $^{181}$Ta.

## Key findings

- Identification of scissors resonance splitting into two parts.
- Determination of $\gamma$ deformation angle of $14.9^{\circ}$ for $^{181}$Ta.
- Comparison of calculated and experimental neutron capture cross sections.

## Abstract

Particle-$\gamma$ coincidence experiments were performed at the Oslo Cyclotron Laboratory with the $^{181}$Ta(d,X) and $^{181}$Ta($^{3}$He,X) reactions, to measure the nuclear level densities (NLDs) and $\gamma$-ray strength functions ($\gamma$SFs) of $^{180, 181, 182}$Ta using the Oslo method. The Back-shifted Fermi-Gas, Constant Temperature plus Fermi Gas, and Hartree-Fock-Bogoliubov plus Combinatorial models where used for the absolute normalisations of the experimental NLDs at the neutron separation energies. The NLDs and $\gamma$SFs are used to calculate the corresponding $^{181}$Ta(n,$\gamma$) cross sections and these are compared to results from other techniques. The energy region of the scissors resonance strength is investigated and from the data and comparison to prior work it is concluded that the scissors strength splits into two distinct parts. This splitting may allow for the determination of triaxiality and a $\gamma$ deformation of $14.9^{\circ} \pm 1.8^{\circ}$ was determined for $^{181}$Ta.