Photonuclear reactions cross-sections at energies up to 100 MeV for different experimental setups

Abstract

In experiments on the electron linac LUE-40 of RDC "Accelerator" NSC KIPT, the flux-averaged cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\exp }$ of photonuclear reactions ${}^{100}\mathrm{Mo}(\gamma ,n{)}^{99}\mathrm{Mo}$, ${}^{27}\mathrm{Al}(\gamma ,x{)}^{24}\mathrm{Na}$, ${}^{93}\mathrm{Nb}(\gamma ,n{)}^{92m}\mathrm{Nb}$, ${}^{93}\mathrm{Nb}(\gamma ,3n{)}^{90}\mathrm{Nb}$, and ${}^{181}\mathrm{Ta}(\gamma ,n{)}^{180g}\mathrm{Ta}$ were measured using the $\gamma$-activation technique. The theoretical flux-average cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{th}}$ were computed using the partial cross-section $\sigma (E)$ values from the TALYS1.9-1.95 codes and bremsstrahlung $\gamma$-flux calculated using GEANT4.9.2. Two different experimental setups were used in the experiments: an aluminum electron absorber and a deflecting magnet to clean the bremsstrahlung $\gamma$-flux from electrons. A comparison of the flux-average cross-sections measured for two experimental setups was performed. The possibility of using the reactions ${}^{100}\mathrm{Mo}(\gamma ,n{)}^{99}\mathrm{Mo}$, ${}^{27}\mathrm{Al}(\gamma ,x{)}^{24}\mathrm{Na}$, ${}^{93}\mathrm{Nb}(\gamma ,n{)}^{92m}\mathrm{Nb}$, ${}^{93}\mathrm{Nb}(\gamma ,3n{)}^{90}\mathrm{Nb}$, and ${}^{181}\mathrm{Ta}(\gamma ,n{)}^{180g}\mathrm{Ta}$ as monitors of the bremsstrahlung $\gamma$-flux for the energy range 30-100 MeV was investigated.

8 pages, 6 figures, 1 table