Thermoluminescence of fluorapatite mineral

Author(s)

Silva, G. P. S. ^[1] ; Nunes, M. C. S. ^[1] ; Ulsen, C. ^[2] ; Kunzel, R. ^[3] ; Yoshimura, E. M. ^[4] ; Trindade, N. M. ^{[4, 1]}

Affiliation

^[1] Fed Inst Educ Sci & Technol Sao Paulo, Dept Phys, Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Escola Politecn, Technol Characterizat Lab, Sao Paulo, SP - Brazil

^[3] Univ Fed Sao Paulo, Dept Phys, Diadema, SP - Brazil

^[4] Univ Sao Paulo, Inst Phys, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Journal of Luminescence; v. 231, MAR 2021.
• Web of Science Citations: 0

Abstract

Fluorapatite {[}Ca-10(PO4)(6)F-2] is a mineral of the apatite group of the highest occurrence in the world among phosphates. The material is known for its diverse luminescent properties, as fluorescent lamps and lasers. The thermoluminescence (TL) signal of apatite from various origins has been investigated in the past years, mainly of the Mexican origin. In this work, the objective was to investigate the TL of samples of the Brazilian natural fluorapatites submitted to beta-ionizing radiation. The chemical composition of the samples was obtained by the technique of X-ray fluorescence and the electronic transitions were verified by optical absorption in the visible region. The mineral presented a wide optical absorption band between 500 nm and 750 nm, typical of fluorapatite, and SEM/EDS showed a high percentage of purity. The registered Raman spectrum exhibits the characteristics modes from the PO43- tetrahedra, observed in fluorapatite, and a band at 1103 cm(-1) characteristic of the (CaO3)(2-) carbonate group. The TL measurements were carried out using a commercial Riso TL/OSL reader, model DA-20, equipped with a built in Sr-90/Y-90 beta source, with different radiation doses (1-5 Gy). The TL glow curve showed three peaks located at about 350 K, 470 K and 570 K (heating rate of 1 K/s). The activation energy and the frequency factor associated with each peak were determined by different methods. In addition, the TL response (area under the peaks) has shown linear behavior in relation to the doses. (AU)

• FAPESP's process: 19/05915-3 - Characterization of minerals for luminescent dosimetry of ionizing radiations
• Grantee: Neilo Marcos Trindade
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/16894-4 - Investigation of optically stimulated luminescence of alexandrite pellets for applications in the dosimetry area
• Grantee: Matheus Cavalcanti dos Santos Nunes
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 19/15599-1 - Investigation of fluorapatite thermoluminescence focusing on dosimetry area
• Grantee: Guilherme Paulino dos Santos Silva
• Support Opportunities: Scholarships in Brazil - Scientific Initiation