Photo-neutron cross-section of natGd in the bremsstrahlung end-point energies of 12-16 MeV and 60-70 MeV

The spectrum-averaged cross-sections of Gd-nat(gamma, xn)Gd-159,Gd-153 reactions induced by the bremsstrahlung end-point energies of 12, 14, 16. 60, 65, and 70 MeV were measured by activation and off-line gamma-ray spectrometric technique using the 20 MeV electron linac (ELBE) at HZDR, Dresden, Germany, and 100 MeV electron linac at Pohang Accelerator Laboratory, Korea. The TALYS 1.9 code was also used to calculate the theoretical Gd-nat(gamma, xn)Gd-159,Gd-153 reaction cross-sections as a function of photon energy. The spectrum-averaged values at various end-point energies were calculated from the literature data as well as theoretical values based on the TALYS 1.9 code, which is for mono-energetic photons. They were found to be in good agreement with the flux-weighted values of the current experimental data. It was also observed that the experimental and theoretical cross-sections increase from the threshold values to a certain energy, at which point another reaction channel opens, indicating the role of excitation energy. Individual reaction cross-sections decrease after a certain value as bremsstrahlung energy increases due to the opening of other reactions, indicating energy shearing among the different reaction channels.

Automated summary

This study measured the spectrum-averaged cross-sections of Gd-nat(gamma, xn)Gd-159,Gd-153 reactions using two different electron linacs and calculated the theoretical values using the TALYS 1.9 code. The experimental results were in good agreement with the theoretical values and literature data. It was observed that the excitation energy played a role in the reaction cross-sections, and energy sharing occurred among different reaction channels as the bremsstrahlung energy increased.