Direct and indirect measurement of photonuclear reactions relevant to medical and reactor physics

Abstract

The generation of photonuclear data is crucial in a variety of fields of science and technology, including nuclear physics, reactor technology, astrophysics, space technology, radiation therapy, and radiation protection. Photonuclear reactions involve the interaction of high-energy photons with atomic nuclei, leading to the emission of nucleons, photons and nuclear clusters as well as fission.High-energy photons are routinely used in radiation therapy. Along with the destruction of cancer tissues, they induce nuclear transmutation. This can be constructively exploited for the production of radioisotopes for medical and industrial applications, for which precise data on the relevant systems are important. In the case of reactor technologies, a significant level of high-energy photons is produced inside fusion reactors as a result of neutron interactions with the structural materials. These energetic photons contribute to hydrogen formation through the photonuclear reactions and result in swelling and stress formation. In fission reactor, photon flux influences the fission process and neutron economy. Currently, the available experimental data shows systematic disagreements, both in shape and magnitude, which reduces the reliability. Hence, the generation of benchmarked photonuclear data are essential. In the first part of the thesis, we have considered 99m Tc and 18 F isotope, relavant in the med- ical imaging area and determined the integral cross section of the reaction 99 Tc(γ, γ0)99m Tc and 19 F(γ,n)18 F, using the photonuclear activation method. 115 In(γ, γ0)115m In and 115 In(γ,n)114m In re- actions have been used as a monitor reaction in each case respectively, for the flux normalization of the bremsstrahlung spectrum. Theoretical model calculations have been done using the nuclear reaction code Talys 1.96. Theoretical parameter values are optimized with the presently obtained data. Energy specific cross sections are evaluated using the optimized theoretical code. In the second part of the thesis, we have considered 58 Co, relavant in reactor environment. Thus, 58 the photonuclear cross section of Co(γ,xp) reaction was studied utilizing the surrogate ratio method(SRM). The compound nucleus 58 Co∗ was populated using the transfer reaction 56 Fe(6 Li,α) at Elab = 35.9 MeV. Reference data taken from the recommended IAEA photonuclear database, which adopted the KAERI data in this case, have been used to determine the desired cross section. Compound nuclear cross section calculations have been done using the statistical nuclear reaction code TALYS 1.96.