Determination of flux-weighted average cross-sections of ^natPb($\gamma$,xn), ²⁰⁸Pb($\gamma$,xn), and ²⁰⁹Bi($\gamma$,xn) reactions using bremsstrahlung end-point energies of 50-70 MeV

Abstract.

The flux-weighted average cross-sections of the ^natPb($\gamma$,xn)^198-204Pb reaction for the bremsstrahlung end-point energies of 50-70MeV were determined by activation and off-line $\gamma$ -ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Korea. The relative cross-sections of the ²⁰⁸Pb($\gamma$,xn)^202-204Pb and ²⁰⁹Bi($\gamma$,xn)^203-206Bi reactions from our earlier work were updated to absolute values and compared with the present data. The photo-neutron cross-sections of ^natPb, ²⁰⁸Pb, and ²⁰⁹Bi were also calculated, as a function of the photon energy using the TALYS 1.6 code. The flux-weighted average cross-sections were obtained from the theoretical values of the TALYS 1.6 code, based on mono-energetic photons, and compared with the present experimental data. The values were found to be in good agreement with the present data for the ²⁰⁹Bi($\gamma$,xn)^203-206Bi, ²⁰⁸Pb($\gamma$,xn)^202-204Pb, and ^natPb($\gamma$,xn)^198-202Pb reactions. However, the present data for the ^natPb($\gamma$,xn)^{203, 204}Pb reactions were higher than the flux-weighted values obtained using the TALYS 1.6 code.