Autor(es)

Fernandes, Caroline Paschoal ; Rocca, Rene Rojas ; Polymeris, Georgios S. ; Cano, Nilo Francisco ; Courrol, Lilia Coronato ; Tatumi, Sonia Hatsue

• Tipo de documento: Artigo Científico
• Fonte: Journal of Luminescence; v. 287, p. 9-pg., 2025-12-25.

Resumo

Sodium borate (SB) glass was investigated as a potential material for thermoluminescent (TL) dosimetry. The TL emission is mainly concentrated in the ultraviolet region (250-400 nm), with glow peaks between 80 degrees C and 200 degrees C. The dose-response is linear from 2 to 1000 Gy, and the minimum detectable dose (MDD) is 58 mGy under standard conditions. To improve signal stability, a preheat step was introduced before TL readout, effectively removing unstable low-temperature components. Under this new condition, the MDD was revised to 160 mGy, and repeatability improved, with a reduced deviation of 4 %. Fading stabilized within 30 min, with only 3 % signal loss. Optical bleaching experiments revealed a gradual TL intensity reduction under blue light exposure, indicating the presence of optically sensitive traps. Electron paramagnetic resonance (EPR) analysis identified two defect centers induced by gamma-irradiation. Among them, a center showing four-line hyperfine splitting was assigned to a boron-oxygen hole center (BOHC) and is associated with the TL peak at 155 degrees C, while another was attributed to an F+ center (peak at 288 degrees C), corresponding to a singly ionized oxygen vacancy. These results support the suitability of SB glass for high dose TL dosimetry applications. (AU)

• Processo FAPESP: 22/02392-2 - Síntese e caracterização de matrizes vítreas de borato de chumbo dopadas com nanopartículas de prata
• Beneficiário: Caroline Paschoal Fernandes
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 22/15495-4 - Datação por LOE e técnicas análiticas aplicadas à bacia do médio Rio Negro, Amazônia: implicações sobre a dinâmica fluvial, sedimentação, modificações da paisagem e ictiofauna
• Beneficiário: Sonia Hatsue Tatumi
• Modalidade de apoio: Auxílio à Pesquisa - Temático