15:30 〜 15:45
▼ [17p-Z18-10] β-MoO3 nanowhiskers in the development of 99Mo/99mTc medical radioisotope preparation using a hot atom mechanism
キーワード：beta-MoO3 nanowhiskers, neutron activation method, hot atom
In the production of Tc-99m (radiopharmaceuticals), the neutron activation (n,γ) method using MoO3 pellet is considered to have more benefits than the nuclear fission products (n,f) method [1]. However, the low specific activity of 99Mo has barred large scale manufacture. Currently, as the 99Mo extraction process in the (n,γ) method, high-density pellets of MoO3 after the irradiating are considered diluted in NaOH solution [2]. Therefore, it consumes time and has difficulties in separating and recovering compounds. Instead of this process, a hydrous MoO3 target has been proposed to overcome these problems and promise to increase the effectiveness of the (n,γ) method using a hot atom mechanism of irradiated samples. This target requires a porous structure with a suitable filtering property. Whisker is a suitable candidate with excellent filtered property. Among MoO3 phases, β-MoO3 is the best catalyst caused by its crystal structure with a larger space among valent binding of Mo and O than the other phases [3]. Therefore, it is a good condition for water can go through and wash the hot atom from the irradiated target. β-MoO3 nanowhiskers were only synthesized by pulsed wire discharge, in which the purity was low [4]. In this research, a β-MoO3 nanowhisker with a width of 10 nm was synthesized by thermal evaporation method with the oxygen gas flow at 750, 800, 850, 900, and 1000 ºC. The samples were characterized and confirmed by XRD in Fig. 1 and lattice image by FE-TEM in Fig. 2. From this work, the high content and purity of β-MoO3 nanowhiskers were synthesized by the thermal evaporation method. This sample is a promising material for the irradiation target in the (n, γ) method.