ISOMERIC RATIO OF THE 181 Ta( γ , 3n) 178m,g Ta REACTION PRODUCTS AT ENERGY E γ max UP TO 95 MeV

The photoneutron reaction \begin{document}$^{181}{\rm{Ta}}(\gamma,3{\rm{n}})^{178{\rm{m,g}}}{\rm{Ta}}$\end{document} was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40. The measurements were performed using the residual γ-activity method. The bremsstrahlung flux-averaged cross-sections \begin{document}$\langle{\sigma(E_{\rm{\gamma max}})}\rangle$\end{document} , \begin{document}$\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{m}}$\end{document} , \begin{document}$\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{g}}$\end{document} and the isomeric ratio of the reaction products \begin{document}$d(E_{\rm{\gamma max}})$\end{document} have been measured. Theoretical values of averaged cross-sections and isomeric ratio were calculated using partial cross-sections from the TALYS1.95 code for different level density models \begin{document}$LD$\end{document} 1-6. The obtained experimental \begin{document}$d(E_{\rm{\gamma max}})$\end{document} agree with the literature data, but differ from the theoretical values in absolute magnitude and the behavior of the energy dependence. A comparison of the found averaged cross-sections with the calculated ones showed the best agreement for the case of the \begin{document}$LD$\end{document} 5 model.