| dc.description.abstract |
The use of cyclotrons to accelerate protons via the bombardment of target substances to produce nuclear reactions has been widely used in the production of artificial radioisotopes, in which the radioisotope fluorine-18 can be made into various types of cancer diagnostic drugs, and thus attracted attention from all walks of life.
The design of the irradiation target has a significant effect on the improvement of the yield of fluorine-18. The designer usually encounters two critical yet conflicting problems during the production process, i.e., corrosion resistance and heat dissipation. Owing to the strong corrosive nature of the fluoric acid, it is necessary to find a target material that is resistant to fluoric acid. In the meantime, a target material should also possess a good heat transfer capability to minimize the overheating phenomenon during the irradiation. However, the existing materials typically cannot meet both requirements simultaneously.
The aim of this study is to design a radiation target system that can operate stably under high power conditions and attempt to sputter a layer of corrosion-resistant tantalum on top of the silver target in an attempt to concurrently achieve good corrosion and heat dissipation.
After the actual irradiation experiment, it has been confirmed that the irradiation target system of this study can run stably under the total power of 1020 (W) and can reach 80% theoretical yield. However, the sputtered tantalum layer undergoes peeling during the irradiation experiment, which clearly indicates the poor adhesion between the silver substrate and sputtered tantalum layer. Therefore, finding the proper intermediate layers to significantly promote the adhesion will be the focus of future research. Neutron flux experiment results, failed to determine the presence of oxygen-18 water in the target cavity, the need for additional experiments in order to obtain further conclusions. | en_US |