PROPRIEDADES DE ATENUAÇÃO DE NANOCOMPÓSITOS PARA USO EM PROTEÇÃO RADIOLÓGICA

• Autor(a) principal: Botelho, Marcel Zago
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional Universidade Franciscana
• Texto Completo: http://tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/241; http://www.tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/338
• topic: Nanociências; Proteção Radiológica; Mamografia; Radiologia Convencional; Nanocompósitos; Radiological Protection; Mammography; Conventional Radiology; Nanocomposites; CNPQ::ENGENHARIAS

The aim of this study is to evaluate the attenuation properties of the nanocomposites in the energy range between 20 and 120 keV. In order to evaluate the efficiency of nanostructured materials in the attenuation of radiation the results will be compared to data obtained with the same material in the non-nanostructured form. The nanostructured materials are characterized by having a size of crystallites less than 100nm, and shows different properties with respect to conventional materials. The nanocomposites used in this study were produced through the aggregation of nanoparticles of copper oxide (CuO) and zinc oxide (ZnO) to beeswax. The concentration of nanoparticles in the composite was varied between 5% and 10%. For comparison purpose the copper oxide and zinc oxide in a non-aggregated nanoparticles were also agregated in a nonnanoparticulated form to beeswax in the same proportion as for nanostructured materials. Samples were produced with dimensions 10 cm x 10 cm and 2 mm in thicknesses. The attenuation properties of the samples produced were evaluated at high energy X-ray beams, emmited by a X-ray equipment used in conventional radiology, and the low energy x-ray beams are produced by a clinical mammography equipment. The air kerma values, for different material thicknesses, were measured with an ionization chamber for x-ray beam produced at 60 kV and 102 kV. Results shows that the attenuation provided by the copper oxide is slighly higher for the nanoestrured materials compared with for the non-nanoestrutured ones. In the case of the zinc oxide, the material in the non-nanometric form shows an increasing of the attenuation relative to the nanoparticulates ones. In the mammography energy range the study was carried out for beams generated at 22, 26 and 30 kV. It is observed that the copper oxide in nanometric structure attenuate at about 23% more radiation than the same material in the non-nanoparticulate form. In the case of the zinc oxide the attenuation is higher at about 7% for the material in the non-nanometric form. This study suggest that nanostructured materials show great potential for application in radiological protection, because it can be easily incorporated into different compounds allowing the development of new materials for use in radiological protection.