Assessment of the thermoluminescent properties of epidote

Abstract

In the literature, little information is found about the crystal structure of epidote; however, there is limited knowledge about the thermoluminescent properties of this mineral. The mineral epidote has the chemical formula Ca2Al2Fe3+[Si2O7][SiO4]O(OH) and exhibits a dark green coloration. A sample of the mineral epidote, collected in Peru, was investigated. As these are naturally occurring samples, the crystallography of each mineral may vary due to damage caused by natural radiation and the climatic conditions of pressure and temperature to which this mineral has been exposed. Therefore, to determine if the thermoluminescent behavior of different epidote samples would be similar, a mineral collected in Brazil was investigated. The samples were pulverized, and grain sizes ranging from 80 to 180 μm in dimension were utilized. The experiments were conducted employing different thermal treatments and gamma radiation doses aiming identifying the best thermal treatment that allows the obtention of an intense and distinct TL signal. Preliminary TL results demonstrated a clear response of samples irradiated with high doses, exceeding 10 kGy, and thermally treated at 900 °C for 1 h, indicating its potential as a dosimeter for industrial applications. The results of the Thermoluminescence (TL) analysis conducted on the epidote sample from Brazil revealed similarities when compared to the TL analyses of the epidote sample from Peru.