We developed new composites for photons shielding applications. The composite were prepared with epoxy resin, red clay and bismuth oxide nanoparticles (Bi₂O₃ NPs). In order to establish which ratio of red clay to Bi₂O₃ NPs provides the best shielding capabilities, several different ratios of red clay to Bi₂O₃ NPs were tested. The transmission factor (TF) was calculated for two different thicknesses of each sample. From the TF data, we found that epoxy resin materials have a high attenuation capacity at low energy. For ERB-10 sample (40%Epoxy + 50% Red clay + 10% Bi₂O₃ NPs), the TF values are 52.3% and 14.3% for thicknesses of 0.5 and 1.5 cm (at 0.06 MeV). The composite which contains the maximum amount of Bi₂O₃ nanoparticles (40%Epoxy + 50% Red clay + 10% Bi₂O₃ NPs, coded as ERB-30) has lower TF than the other composites. The TF data demonstrated that ERB-30 is capable of producing more effective attenuation from gamma rays. We also determined the linear attenuation coefficient (LAC) for the prepared composites and we found that the LAC increases for a given energy in proportion to the Bi₂O₃ NPs ratio. For the ERB-0 (free Bi₂O₃ NPs), the LAC at 0.662 MeV is 0.143 cm⁻¹, and it increases to 0.805 cm⁻¹ when 10% of Bi₂O₃ NPs is added to the epoxy resin composite. The half value layer (HVL) results showed that the thickness necessary to shield that photons to its half intensity can be significantly lowered by increasing the weight fraction of the Bi₂O₃ NPs in the epoxy resin composite from 0 to 30%. The HVL for ERB-20 and ERB-30 were compared with other materials such as (Epoxy as a matrix material and Al₂O₃, Fe₂O₃, MgO and ZrO₂ as filler oxides in the matrix at 0.662 MeV. The HVL values for ERB-20 and ERB-30 are 4.385 and 3.988 cm and this is lower than all the selected epoxy polymers.

In this work, we studied the effect of bismuth oxide particle size and its attenuation capacity as a filler additive in epoxy resins. Six samples were prepared according to the amount of microparticles and nanoparticles in the sample and were coded as ERB-1, ERB-2, ERB-3, ERB-4, ERB-5, and ERB-6. One of the composite epoxies contained Bi₂O₃ microparticles at a 50:50 ratio (ERB-6) and was chosen as the control composite, and the number of microparticles (MPs) was gradually decreased and replaced by nanoparticles (NPs) to produce epoxy-containing Bi₂O₃ nanoparticles at a 50:50 ratio (ERB-1). The morphological and thermal characteristics of the studied composites were tested. The attenuation capability of the prepared composites, which is determined by the Bi₂O₃ particle size, was determined experimentally using a semiconductor detector, an HPGe-detector, and three different gamma-ray point sources (Am-241, Co-60, and Cs-137). The linear attenuation coefficient (LAC) of ERB-3, which contained 30% nanoparticles and 20% microparticles, had the highest value compared to the other composites at all the energies discussed, while the ERB-6 composite had the lowest value at all energies. The radiation-shielding efficiency (RSE) of the prepared samples was determined at all discussed energies; at 662 keV, the radiation-shielding efficiency values were 15.97%, 13.94%, and 12.55% for ERB-3, ERB-1, and ERB-6, respectively. The statistics also proved that the attenuation capacities of the samples containing a combination of nanoparticles and microparticles were much superior to those of the samples containing only microparticles or nanoparticles. A ranking of the samples based on their attenuation capacity is as follows: ERB-3 > ERB-4 > ERB-2 > ERB-1 > ERB-5 > ERB-6.

This study aims to investigate the impact of CeO₂ content and particle size on the radiation shielding abilities of polydimethylsiloxane, also known as silicon rubber (SR). We prepared different SR samples with 10, 30, and 50% of micro and nano CeO₂ and we measured the linear attenuation coefficient (LAC) for these samples. We found that the LAC of the SR increases by increasing the CeO₂ and all prepared SR samples had higher LACs than the pure SR. We examined the effect of the size of the particles on the LAC and the results demonstrated that the LAC for nano CeO₂ is higher than that of micro CeO₂. We investigated the half value layer (HVL) for the prepared SR samples and the results revealed that the SR with 10% micro CeO₂ had a greater HVL than the SR with 10% nano CeO₂. The HVL results demonstrated that the SR containing nanoparticles had higher attenuation effectiveness than the SR with micro CeO₂. We also prepared SR samples containing CeO₂ in both sizes (i.e., micro and nano) and we found that the HVL of the SR containing both sizes was lower than the HVL of the SR with nano CeO₂. The radiation protection efficiency (RPE) at 0.059 MeV for the SR with 10% micro and nano CeO₂ was 94.2 and 95.6%, respectively, while the RPE of SR containing both sizes (5% micro CeO₂ + 5% micro CeO₂) was 96.1% at the same energy. The RPE results also indicated that the attenuation ability was improved when utilizing the micro and nano CeO₂ as opposed to the micro CeO₂ or nano CeO₂ at 0.662, 1.173, and 1.333 MeV.

In an attempt to reutilize marble waste, a new approach is presented in the current study to promote its use in the field of shielding against ionizing radiation. In this study, we aimed to develop a novel and sustainable/eco-friendly lead-free radiation shielding material by improving artificial marble (AM) produced from marble waste combined with polyester by reinforcing it with bismuth oxide (Bi₂O₃) nanoparticles. Six samples of AM samples doped with different concentrations ($0\%$,$5\%$,$10\%$,$15\%$, $20\%$, and $25\%$) of Bi₂O₃ nanoparticles were prepared. The linear attenuation coefficient ($LAC$) values were measured experimentally through the narrow beam method at different energies $(0.0595 \mathrm{M}\mathrm{e}\mathrm{V}$, $0.6617 \mathrm{M}\mathrm{e}\mathrm{V}$, $1.1730 \mathrm{M}\mathrm{e}\mathrm{V}$, and $1.330 \mathrm{M}\mathrm{e}\mathrm{V}$) for all samples with various concentrations of Bi₂O₃. Radiological shielding parameters such as half value layer ($HVL$), tenth-value layer ($TVL$), and radiation shielding efficiency ($RSE$) were estimated and compared for all the different samples. The results prove that increasing the concentration of Bi₂O₃ leads to the enhancement of the radiation shielding properties of the AM as a shielding material. It was observed that as the energy increases, the efficiency of the samples falls. High energy dependence was found when calculating the $HVL$ and $TVL$ values of the samples, which increased with increases in the energy of the incident photons. A comparison between the sample with the most efficient gamma radiation attenuation capability (AM-$25\%$), concrete, and lead was conducted, and a discussion regarding their radiation shielding properties is presented herein. The results show that the AM-$25\%$ sample is superior to the ordinary concrete over all the studied energy ranges, as evidenced by its significantly lower $HVLs$. On the contrary, lead is superior to the AM-$25\%$ sample over all the studied energy ranges owing to its unbeatable density as a shielding material. Overall, this new type of artificial marble has the potential to be used as a radiation shielding material at low- to medium-gamma energy regions, specifically in medical imaging and radiation therapy.