Isostatic hot-pressed tungsten radiation shields against gamma radiation
Д.И. Тишкевич, S.A. German, A.A. Rotkovich, T. N. Vershinina, А. L. Zhaludkevich, Yuan Yao, Maksim V. Silibin, Ihar Razanau, T.I. Zubar, Anastasia A. Bondaruk, M.I. Sayyed, А.В. Труханов
Abstract
An isostatic hot-pressing technique for the fabrication of dense W samples’ is presented. The samples’ microstructure and chemical content were analyzed. The most compact samples were received at 5 GPa pressure and 1500 and 2000 °C temperatures, with densities of 18.50 and 19.07 g/cm3, respectively. It has been established that high temperature exposure has a positive effect on both the microstructure and density. It is shown that as the sintering temperature increases, the porosity of the samples decreases from 32.31% to 0.94%, and their relative density increases from 67.69% to 99.06%. The crystal structure investigation revealed that all the samples contain the main body-centered cubic W phase, and the availability of the WO2 phase is observed just after the temperature of sintering increases above 1000 °C, which is confirmed by the appearance of 111 and 22-2 reflections. A study of the shielding effectiveness against gamma-radiation was carried out using the Phy-X/PSD software. A gamma-ray source of Co60 with energies of 0.8-2.5 MeV was applied for the calculations. The results were calculated for the sample with the highest density (19.07 g/cm3) and compared with the calculations for Pb. The W shielding effectiveness main parameters are determined: linear attenuation coefficient (at 0.8 MeV – 1.46 cm-1), mean free path (at 2.5 MeV – 1.2 cm) and half value layer (at 2.5 MeV – 0.86 cm). These values turned out to be higher than for Pb, which makes shields based on W promising for use in the field of radiation protection.