Measurement of the flux-weighted cross-sections for the ^natYb(γ,xn)^175,169,167Yb reactions in the Bremsstrahlung end-point energies of 12-16 MeV and 60-70 MeV

Abstract

The flux-weighted cross-sections of the Yb-nat(gamma, xn)Yb-175,Yb-169,Yb-167 reactions were measured at the bremsstrahlung end-point energies of 12, 14, 16, 60, 65, and 70 MeV by the activation and off-line gamma-ray spectrometric technique using the 20 MeV electron linac (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany, and 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Korea. The Yb-nat(gamma, xn)Yb-175,Yb-169,Yb-167 reaction cross-sections as a function of photon energy were also calculated theoretically using the TALYS 1.9 code. The flux-weighted average values at different end-point energies were obtained from the literature as well as from the theoretical values reported in the TALYS library based on mono-energetic photons. They were compared with the flux-weighted values based on the present experimental data and were found to be in general agreement. It was also found that the experimental and theoretical cross-section data increased from the threshold values to a certain energy, where other reaction channels opened, which highlights the role of excitation energy. After a certain value, the individual reaction cross-sections decrease with an increase in bremsstrahlung energy owing to the opening of other reaction channels, which indicates the partitioning of energy in different reaction channels.