Multilayer Electrophoretic Deposition for Gamma Attenuation

For the first time the electrophoretic deposition method was used to deposit multilayer oxides on iron discs for gamma attenuation. The following powders: W₁₀O₂₉, Bi₂O₃, and Pb-PbO, were deposited separately on both sides of iron discs. Eleven coated Fe discs with an oxide were put on each other and preserved by pouring epoxy on them to form three multilayer samples: Fe coated plates with W₁₀O₂₉, with Bi₂O₃, and with Pb-PbO. Another group (mixture samples), was prepared by mixing each oxide separately with micro Fe particles (instead of the Fe plate) and epoxy. The weights of each component for the second group were the same as those for the first one. The characterization of powders was investigated by the X-ray diffraction tests. The scanning electron microscopy images showed that the particle sizes averages for W₁₀O₂₉, Bi₂O₃, and Pb-PbO were 60, 40, and 66 nm, respectively. The transmission factor percentage, the radiation protection efficiency, and theoretical as well as experimental linear attenuation coefficient of multilayer and mixture samples have been experimentally determined for five different gamma energies emitted from the Eu-152 radioactive source by using a gamma spectrometry system with a NaI(Tl) detector. The percentage of the transmission factors of multilayer samples was lower than that of uncoated Fe layers and mixture samples. At a low gamma energy, for both groups (multilayer and mixture samples) there was a mismatch between the practical and theoretical linear attenuation coefficient curves. Those Fe coated with Pb-PbO had a higher linear attenuation coefficient than other samples. All multilayer samples had greater buildup factor values-around 121 keV, and lower buildup factor values in the high and low energy ranges.