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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. [ABSTRACT FROM AUTHOR]

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 ( L A C ) values were measured experimentally through the narrow beam method at different energies (0.0595   M e V , 0.6617   M e V , 1.1730   M e V , and 1.330   M e V ) for all samples with various concentrations of Bi2O3. Radiological shielding parameters such as half value layer ( H V L ), tenth-value layer ( T V L ), and radiation shielding efficiency ( R S E ) 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 H V L and T V L 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 H V L s . 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]