Photoproduction of the ${}^{55-57}$Co nuclei on ${}^{\mathrm{nat}}$Ni at the bremsstrahlung end-point energy of 35-94 MeV

Abstract

Production of the ${}^{55-57}$Co nuclei on ${}^{\mathrm{nat}}$Ni in photonuclear reactions using bremsstrahlung gamma photon irradiation with end-point energy $E_{\gamma \max }$ 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 $\gamma$ activation and off-line $\gamma$-ray spectroscopy. The obtained experimental flux-averaged cross-sections $⟨\sigma (E_{\gamma \max })⟩$ agree with the data found in literature. The theoretical flux-averaged cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{th}}$ for the production of ${}^{55-57}$Co and ${}^{55-57}$Ni were estimated using the cross-section values $\sigma (E)$ 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 $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{th}}$. However theoretical prediction fails to reproduce the measured cross-sections for the production of ${}^{55}$Co.

11 pages, 6 figures, 4 Tables