Structural, optical and thermoluminescence properties of amazonite

Author(s)

Martins, R. T. E. K. ; Kunzel, R. ; Ulsen, C. ; Yoshimura, E. M. ; Trindade, N. M.

• Document type: Journal article
• Source: Radiation Physics and Chemistry; v. 223, p. 10-pg., 2024-06-28.

Abstract

This study presents an analysis of the structural and thermoluminescence properties of amazonite, a feldspar species. The characterization was done using X-ray diffraction (XRD), X-ray fluorescence (XRF), optical spectroscopy, and vibrational spectroscopies such as Raman and Fourier Transform Infrared (FTIR). The sample exhibits a partial (Al, Si) ordenation, and contains an albite phase in addition to microcline. FTIR and Raman indicated the presence of water and OH- vibration modes. Optical absorption measurements highlighted the influence of the hydroxyl groups as catalyst for Pb transitions, contributing to the coloration of amazonite. Thermoluminescence (TL) studies were performed within a dose range from 0.1 to 10 Gy using a built-in beta source ( 90 Sr/ 90 Y; delivering 10 mGy/s), showing seven TL glow peaks based on non-first kinetic order. The sample exhibited a linear dose-response, with TL signals proving to be both repeatable and reproducible (CV similar to 2%). Fading analysis showed the first two TL peaks disappear after 16 days of dark storage. Thermal quenching behavior was investigated under various heating rates, demonstrating a decrease in luminescence efficiency with increasing heating rates. Additionally, the activation energies were determined using different methods, and the amazonite TL glow curve presented activation energies values within 0.7 to 2 eV. (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: 22/07200-4 - Characterization of the optical and thermoluminescent properties of amazonites.
• Grantee: Roberto Turibio Ebina Kawanaka Martins
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/05982-0 - R&D&I in radiation metrology in the health area
• Grantee: Linda Viola Ehlin Caldas
• Support Opportunities: Research Projects - Thematic Grants