Gamma Attenuation Features of White Cement Mortars Reinforced by Micro/Nano Bi 2 O 3 Particles.

This study aims to explore the radiation protection properties of white mortars based on white cement as a binder and Bi 2 O 3 micro and nanoparticles in proportions of 15 and 30% by weight as replacement sand. The average particle size of micro- and nano-Bi 2 O 3 was measured using a transmission electron microscope (TEM). The cross-sectional morphology and distribution of Bi 2 O3 within the samples can be obtained by scanning electron microscopy (SEM), showing that nanoscale Bi 2 O 3 particles have a more homogeneous distribution within the samples than microscale Bi 2 O 3 particles. The shielding parameters of the proposed mortars were measured using the HPGe detector at various γ-ray energies emitted by standard radioactive point sources 241 Am, 133 Ba, 60 Co, 137 Cs, and 152 Eu. The experimental values of the prepared mortars' mass attenuation coefficients (MAC) match well with those determined theoretically from the XCOM database. Other shielding parameters, including half value layer (HVL), tenth value layer (TVL), mean free path (MFP), effective electron density (N eff ), effective atomic number (Z eff ), equivalent atomic number (Z eq ), and exposure buildup factor (EBF), were also determined at different photon energies to provide more shielding information about the penetration of gamma radiation into the selected mortars. The obtained results indicated that the sample containing 30% by weight of nano Bi 2 O 3 has the largest attenuation coefficient value. Furthermore, the results show that the sample with a high concentration of Bi 2 O 3 has the highest equivalent atomic numbers and the lowest HVL, TVL, MFP, and EBF values. Finally, it can be concluded that Bi 2 O 3 nanoparticles have higher efficiency and protection compared to microparticles, especially at lower gamma-ray energies.