Photoproduction of the ${^{55-57}}$Co nuclei on ${^{\rm nat}}$Ni at the bremsstrahlung end-point energy of 35-94 MeV
Production of the ${^{55-57}}$Co nuclei on ${^{\rm nat}}$Ni in photonuclear reactions using bremsstrahlung gamma photon irradiation with end-point energy $E_{\rm{γmax}}$ between 35 and 94~MeV has been studied. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT using the methods of $γ$ activation and off-line $γ$-ray spectroscopy. The obtained experimental flux-averaged cross-sections $\langle{σ(E_{\rm{γmax}})}\rangle$ agree with the data found in literature. The theoretical flux-averaged cross-sections $\langle{σ(E_{\rm{γmax}})}\rangle_{\rm{th}}$ for the production of ${^{55-57}}$Co and ${^{55-57}}$Ni were estimated using the cross-section values $σ(E)$ from the TALYS1.95 code and bremsstrahlung spectra of gamma photons calculated by GEANT4.9.2. The experimental results for ${^{56,57}}$Co agree with the cumulative $\langle{σ(E_{\rm{γmax}})}\rangle_{\rm{th}}$. However theoretical prediction fails to reproduce the measured cross-sections for the production of ${^{55}}$Co.