Produção de filmes de CdWO4 em matriz polimérica para aplicação como sensores de radiação

• Ano de defesa: 2022
• Autor(a) principal: Monteiro, Thaise de Jesus
• Orientador(a): Macedo, Zélia Soares
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Física
• Palavras-chave em Português: Compósitos; CdWO4; Poliestireno
• Palavras-chave em Inglês: Composites; Polystyrene
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/16926

In this work, the CdWO4 scintillator was synthesized through the microwave-assisted hydrothermal route and applied in the making of polystyrene (PS) composite films. The single crystalline phase of CdWO4 was obtained at 120ºC for 60 minutes, in suspension of metal oxides under pH=10. Then, films of various thicknesses were produced using the casting technique. As the microtomography results showed that the scintillator was concentrated majority on a single side of the film, the superficial modification of CdWO4 particles with stearic acid was performed in order to improve the chemical affinity between the scintillator (inorganic) and the polymer (organic). The use of acid as a modifying agent of particles, and variations in the concentration of PS solution, resulted in the optimization of the film confection process. Presenting the is composites a homogeneous distribution of the scintillator in the polymer matrix, with the increase of the concentration of the PS solution and with the use of surface modification. The optical characterization of the scintillating composites was performed through the techniques of photoluminescence (PL), radioluminescence (RL), transmission and optical absorption (AO). The results showed that the composites present the characteristic emission of the tungstate groups, with a maximum of 490 nm. When exposed to high doses of soft X-rays, there was the formation of color centers in polystyrene, however, polymer degradation did not result in significant loss of luminescent efficiency. The performance of composites as luminescent screen in the formation of images was tested through microtomography experiments performed at the IMX beamline of the National Synchrotron Light Laboratory (LNLS). The results show that CdWO4-PS films manufactured at low cost are able of forming radiographic images with resolution comparable to the commercial detector (LuAG:Ce) used at the IMX beamline , which makes the luminescent screens presented in this work a simple and economical option to be applied in the formation of X-ray images.