Studies of Yields of ($$\gamma,{xn}$$) Reactions on Natural Iridium at the Bremsstrahlung End-Point Energy of 55 MeV

The article presents the results of the study of the flux-weighted average cross sections of $${}^{185-190}$$ Ir and $${}^{192}$$ Ir nuclei production in ( $$\gamma,xn$$ ) reactions when a natural mixture of iridium isotopes is irradiated with bremsstrahlung with an end-point energy of 55 MeV. For the first time, the experimental data on the weighted average cross sections of photoneutron reactions with the emission of up to six particles are compared with the theoretical weighted average cross sections calculated in the constant-temperature Fermi gas model and the Gogny–Hartree–Fock–Bogoliubov nuclear mass model using the TALYS1.96 program code. It is shown that the cross sections of the studied reactions are simultaneously successfully described only by the constant-temperature Fermi gas model taking into account the pre-equilibrium processes.