Measurement of photo-neutron cross-sections of 89Y with bremsstrahlung energies of 45 and 55 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 in the end-point bremsstrahlung energies of 45 and 55 MeV have been determined for the first time by an activation and an off-line gamma-ray spectrometric techniques using the electron linear accelerator in Pohang accelerator laboratory. The photon-induced reaction cross-sections of Y-89 as a function of photon energy were calculated using the TALYS 1.4. The flux-weighted average cross-sections were obtained from the existing experimental data and the theoretical values of the TALYS 1.4 with the mono-energetic photons. The present results for Y-89(gamma, xn; x = 1-4) reactions are compared with the flux-weighted average values from the literature and those from the TALYS 1.4. It was shown that the Y-89(gamma, xn, x = 1-4) reaction cross-sections increase sharply from their threshold values to certain energies, where other reaction channels opens. Then it remains constant a while, where the next reaction channel increases. There after it decrease slowly with increase of bremsstrahlung energy due to opening of different reaction channels.