Assessment of radiation attenuation properties for novel alloys: An experimental approach

Mechanical, Morphological, Thermal and the Attenuation Properties of Heavy Mortars Doped with Nanoparticles for Gamma-Ray Shielding Applications

This study aimed to develop a mortar composite with improved gamma ray shielding properties using WO₃ and Bi₂O₃ nanoparticles, as well as granite residue as a partial replacement of sand. The physical properties and effects of sand substitution and nanoparticle addition on the mortar composite were analyzed. TEM analysis confirmed the size of Bi₂O₃ and WO₃ NPs to be 40 ± 5 nm and 35 ± 2 nm, respectively. SEM images showed that increasing the percentage of granite residues and nanoparticles improved the homogeneity of the mixture and decreased the percentage of voids. TGA analysis indicated that the thermal properties of the material improved with the increase in nanoparticles, without decreasing the material weight at higher temperatures. The linear attenuation coefficients were reported and we found that the LAC value at 0.06 MeV increases by a factor of 2.47 when adding Bi₂O₃, while it is enhanced by a factor of 1.12 at 0.662 MeV. From the LAC data, the incorporation of Bi₂O₃ nanoparticles can greatly affect the LAC at low energies, and still have a small but noticeable effect at higher energies. The addition of Bi₂O₃ nanoparticles into the mortars led to a decrease in the half value layer, resulting in excellent shielding properties against gamma rays. The mean free path of the mortars was found to increase with increasing photon energy, but the addition of Bi₂O₃ led to a decrease in MFP and better attenuation, making the CGN-20 mortar the most ideal in terms of shielding ability among the prepared mortars. Our findings on the improved gamma ray shielding properties of the developed mortar composite have promising implications for radiation shielding applications and granite waste recycling.

Grafting red clay with Bi2O3 nanoparticles into epoxy resin for gamma-ray shielding applications

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.

Grafting of heavy metal oxides onto pure polyester for the interest of enhancing radiation shielding performance

In the interest of obtaining new polyester, heavy metal oxides PbCO3, Bi2O3, and CdO with numerous ratios have been added to the polyester resin. Five samples of labeled PR-1, PR-2, PR-3, PR-4, and PR-5 were prepared for this study. The values of linear attenuation coefficients (LAC) of the new polyester samples were measured using an HPGe detector. In the interest of ensuring the experimental setup, the value of LAC obtained from the HPGe detector as well as the value of LAC calculated using Phy-X software, have both been placed in one graph, which revealed a consistent result. The experimental value of those new polyester samples has been measured within the energy region 0.06–1.332 MeV, whereas the theoretical values have been calculated within the energy limit of 0.015–15 MeV. The results of all the new polyester samples showed an uplifting trend according to the rising energy at 0.06, 0.66, 1.17, and 1.33 MeV. At energy 0.06 MeV, sample PR-5 (ρ = 2.180 g/cm3) showed the lowest half value layer (HVL) among the polyester samples. This result is due to the addition of Bi2O3 and CdO into the samples’ composition, increasing their density and enhancing the polyester’s reduction ability. Considering the measured shielding parameters studied herein, it has been found that sample PR-5 (50 wt% Polymer resin, 25 wt% Bi2O3, 25 wt% CdO) had the highest shielding ability compared with the rest of the polyester samples.

Shielding Capability Research on Composite Base Materials in Hybrid Neutron-Gamma Mixed Radiation Fields

The ¹⁶N monitoring system operates in a mixed neutron-gamma radiation field and is subject to high background radiation, thus triggering instability in the ¹⁶N monitoring system measurement data. Due to its property of actual physical process simulation, the Monte Carlo method was adopted to establish the model of the ¹⁶N monitoring system and design a structure-functionally integrated shield to realize neutron-gamma mixed radiation shielding. First, the optimal shielding layer with a thickness of 4 cm was determined in this working environment, which had a significant shielding effect on the background radiation and improved the measurement of the characteristic energy spectrum and the shielding effect on neutrons was better than gamma shielding with the increase in the shield thickness. Then, functional fillers such as B, Gd, W, and Pb were added to the matrix to compare the shielding rates of three matrix materials of polyethylene, epoxy resin, and 6061 aluminum alloy at 1 MeV neutron and gamma energy. The shielding performance of epoxy resin as the matrix material was better than that of the aluminum alloy and polyethylene, and the shielding rate of boron-containing epoxy resin was 44.8%. The γ-ray mass attenuation coefficients of lead and tungsten in the three matrix materials were simulated to determine the best material for the gamma shielding performance. Finally, the optimal materials for neutron shielding and gamma shielding were combined, and the shielding performance of single-layer shielding and double-layer shielding in mixed radiation field was compared. The optimal shielding material-boron-containing epoxy resin was determined as the shielding layer of the ¹⁶N monitoring system to realize the integration of structure and function, which provides a theoretical basis for the selection of shielding materials in a special working environment.

Shielding Properties of Epoxy Matrix Composites Reinforced with MgO Micro- and Nanoparticles

The aim of the current study is to investigate the impact of introducing micro- and nanoparticle MgO as a filler into epoxy resin on the radiation shielding abilities of the prepared samples. To this end, we performed a gamma-radiation spectroscopy experiment with the help of an HPGe detector and Am-241, Cs-137, and Co-60 sources. We evaluated the particle size effect (PSE) and detected the maximum PSE value with the addition of 50 wt% MgO particles, indicating that nanoparticle MgO was more successful in shielding against incoming radiation than microparticle MgO. We compared the half-value layer (HVL) for the samples with 10 wt%, 20 wt%, and 30 wt % micro-MgO and nano-MgO and found that the HVL values were lower for the nanoparticle samples than for the microparticles samples, confirming that smaller particle sizes enhanced the shielding ability of the samples against radiation. The MFP results showed that epoxy matrices containing micro-MgO, for all investigated energies, resulted in higher MFP values that those containing nano-MgO.

Investigation of the Gamma-ray Shielding Performance of CuO-CdO-Bi2O3 Bentonite Ceramics

The purpose of this research is to identify the radiation shielding capability of ceramics adding CuO, CdO, and Bi₂O₃ with diverse wt (%). The chemical compositions of the raw ceramics were documented through Energy Dispersive X-ray “EDX” techniques. For aesthetic appeal and solidification, CuO has been chosen to be added to ceramic. Moreover, in the interest of increasing the radiation shielding ability, the high atomic number and density of both CdO and Bi₂O₃ were suggested for the raw ceramics. To obtain the morphological features of the prepared ceramic samples, a Scanning Electron Microscope, or SEM, was utilized. To verify the experimental results, the MCA value obtained from the Phy-X software was compared to the experimental value collected from the HPGe detector. At energies 0.06 MeV, 0.662 MeV, 1.173 MeV, and 1.333 MeV the linear and mass attenuation coefficients of the prepared ceramics have been measured using a high purity germanium “HPGe” detector as well as three different point sources. Moreover, the relationship between ln(I) and the thickness of the ceramics has been presented here, and the comparison between the LAC of the prepared ceramics with other materials has also been displayed. Bentonite ceramic containing CuO (15 mol %)-CdO (15 mol %)-Bi₂O₃ (20 mol %) with density 3.6 showed the lowest HVL, MFP, and TVL at all studied energies, yet pure Bentonite ceramic containing only CuO (50 mol %), having density 3.4, presented the greatest values. Hence, it can be concluded that the addition of CdO and Bi₂O₃ enhances the radiation shielding ability.