Cross-sections of photoneutron reactions on $^{181}$Ta at $e_{\rm \gamma max}$ up to 95 MeV

TL;DR

This study measures bremsstrahlung flux-averaged cross-sections for photonuclear reactions on tantalum-181 up to 95 MeV and compares experimental results with theoretical predictions, finding good agreement especially with the microscopic level density model LD5.

Contribution

It provides new experimental data on photonuclear cross-sections for $^{181}$Ta at high energies and evaluates theoretical models against these measurements.

Findings

Experimental cross-sections agree with TALYS predictions for 1-4, 6, 7 neutron emissions.

The LD5 model best matches the experimental data among tested level density models.

Good agreement observed up to 95 MeV photon energy.

Abstract

The total bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ for the photonuclear reactions $^{181}\rm{Ta}(\gamma,\textit{x}n; \textit{x} \leq 8)^{181-\textit{x}}\rm{Ta}$ have been measured in the range of end-point energies $E_{\rm \gamma max}$ up to 95 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the activation and off-line $\gamma$-ray spectrometric technique. The calculation of average cross-sections was carried out using the cross-section values computed with the TALYS1.95 code for different level density models $LD$ 1-6. A comparison between the experimental total cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the theoretical values has shown satisfactory agreement for the $^{181}\rm{Ta}(\gamma,\textit{x}n)$ reactions with the escape of 1-4, 6 and 7 neutrons. The closest agreement with the measured data is observed with the $LD$5 computation version, which represents the microscopic level density model taking into account Hilaire's combinatorial tables.