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Study of the optical and thermoluminescent properties of Brazilian alexandrites

Grant number: 20/15626-6
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): March 01, 2021
Effective date (End): February 28, 2022
Field of knowledge:Engineering - Mining Engineering - Mineral Prospecting
Principal researcher:Neilo Marcos Trindade
Grantee:Alexia Oliveira Silva
Home Institution: Instituto Federal de Educação, Ciência e Tecnologia de São Paulo (IFSP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Alexandrite (BeAl2O4: Cr3 +) is one of the varieties of chrysoberyl that is widely found in Brazil and has recently been studied to act as a dosimetric material because its composition combines BeO and Al2O3, oxides most used commercially as a dosimeter. As it is a mineral with potential for dosimetric use, it is important to have knowledge of the effects of ionizing radiation in the absorption and emission centers of the material, based on the use of optical absorption and thermoluminescence (TL) techniques. Preliminary studies with beta radiation have shown that alexandrite exhibits five TL peaks (heating rate 1ºC / s) ~ 80ºC (I), 130ºC (II), 170ºC (III), 260ºC (IV) and 310ºC (V), of which the last two peaks have dosimetric characteristics. From the TL emission curve, it is possible to obtain kinetic parameters, such as energy, frequency factor and kinetic order of the possible dosimetric peaks, which describe the luminescent characteristics of the material. In addition, to verify the influence of ionizing radiation on the optical properties of alexandrite, the effects of pre- and post-irradiation on the optical absorption bands, in the ultraviolet - visible region, will be investigated. The chemical composition of the samples will be obtained through microanalysis by scanning electron microscopy (SEM). The research will be carried out in collaboration with the University of São Paulo.

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