Avaliação do potencial de rochas sedimentares do grupo Itararé e Neossolos como material para blindagem de radiações

Abstract

In recent years, there has been a significant increase in the number of studies on the feasibility of using low-cost natural materials for radiation shielding. Typically, dense materials composed of elements with high atomic numbers are employed for shielding, but such materials are costly and often toxic. In this regard, the search for materials like soils and rocks has proven to be an interesting alternative. This study examines the possibility of using a neossolo litólico and its rock of origin as materials for radiation shielding. Samples were collected in the municipality of Balsa Nova, in the state of Paraná, Brazil. Soil and sedimentary rock samples obtained along the same profile were analyzed in different layers. The chemical composition of the samples was obtained using X-ray fluorescence technique. Based on elemental analysis, the following physical parameters were calculated: linear attenuation coefficient (μ), mass attenuation coefficient (μm), mean free path (MFP), half-value layer (HVL), tenth-value layer (TVL), exposure buildup factor (EBF), energy absorption buildup factor (EABF), and fast neutron removal cross section (FNRCS). The computational code Phy-X was used to calculate radiation interaction parameters. Additionally, the Monte Carlo method was employed using the FLUKA software, which allowed the calculation of μ demonstrating good agreement with the results obtained by Phy-X. The results show that radiation shielding depends on the energy of incident photons and dominant interaction processes. At lower energies, where the photoelectric effect predominates, the chemical composition greatly influences the results, with samples containing higher amounts of Fe2O33 showing higher shielding efficiency. As energy increases, photon attenuation becomes almost independent of the chemical composition of the samples, resulting in higher values of MFP, HVL, and TVL, which are similar among the studied samples. In the intermediate energy region, where incoherent scattering is the main interaction mechanism, the chemical composition has no influence on the results. However, this region exhibited higher values of EBF and EABF, indicating a greater radiation accumulation in the material than in air. Only the highest energy (10 MeV) analyzed showed significant influence of pair production on shielding parameters, mainly influenced by differences in the chemical composition of the samples. Based on the results obtained, it is observed that the differences in shielding parameters between soil and rock were only perceived at lower energies; as the energy increases, the differences become subtle. Finally, the analyzed samples showed good results in radiation shielding.