89Y(γ,xn) reaction cross-section measurements with bremsstrahlung end-point energies of 50-65 MeV

The cross-sections for Y-89(gamma, n)Y-88, Y-89(gamma, 2n)Y-87, Y-89(gamma, 3n)Y-86, and Y-89(gamma, 4n)Y-85 reactions for the end-point bremsstrahlung energies of 50 and 65 MeV were determined by using an activation and an off-line gamma-ray spectrometric techniques with the electron linear accelerator at the Pohang Accelerator laboratory (PAL), Korea. The photon-induced reaction cross-sections of Y-89 as functions of the photon energy were taken from the TENDL-2013 nuclear data library based on the TALYS 1.6 program. For comparison with our experimental results, the flux-weighted average cross-sections for the existing experimental data with mono-energetic photons and the theoretical values from TENDL-2013 were obtained. The reaction cross-section values measured at different end-point bremsstrahlung energies from the present work and from literature are found to be in good agreement with the theoretical values. The Y-89(gamma, xn, x = 1 - 4) reaction cross-sections were observed to increase sharply from their threshold values to certain energies, until the next reaction channel opens, after which it remained constant for a while until the next reaction channel opened. Then, it decrease slowly with increasing of end-point bremsstrahlung energy due to the opening of different reaction channels.