Investigation of photoneutron reaction cross-sections in medical linacs in beamline

In terms of radiation protection principles, photonuclear reactions that could happen in the heads of medical linear accelerators are crucial. In addition to the photon energies used to realize these reactions, the fundamental properties of the interacting materials also play a significant role. Hence, in this thesis study, (γ,n) reaction cross sections for various isotopes of Ti, V, Fe, Mn, Ni, Cu, Mo, Ta, W, Re and Au elements that are primarily found in medical linear accelerator heads and (γ,xn) reaction neutron emission spectra for particular isotopes were explored. Reaction cross-section calculations were performed with TALYS 1.95 computer code using different level density and gamma strength function models. The experimental data obtained from the EXFOR database was evaluated and compared graphically with the calculated cross-section values. For the specified photon input energies, the neutron emission spectra were calculated using the TALYS 1.95 computer code, and their graphical analyses were performed. Nuclear level density and gamma strength function calculation results were generally found to be in agreement with the experimental data. With the modifications to be made in some GDR parameters, it has been determined that cross-section values may be obtained that are more similar to the experimental data. For the isotopes 63Cu, 65Cu, 186W, 187Re, neutron spectra at specific photon incoming energy also yielded significant knowledge on the potential neutron energies to be emitted. KEYWORDS: Giant dipole resonance, gamma strength function, linac head, medical linac, nuclear level density, photoneutron.