Analysis of thermoluminescent glow peaks of zoisite under beta irradiations

摘要

In this study, the thermoluminescence (TL) properties of natural crystal of zoisite were investigated after beta (~(90)Sr) irradiation at room temperature (RT). Zoisite, of chemical formula Ca_2Al_3(SiO_4)(Si_2O_7)O(OH), is found in Minas Gerais State, Brazil as natural mineral of silicate, member of the epidote group. The glow curve of a natural sample submitted to a heat treatment at 600 °C is composed of two broad peaks, centered at about 110-130 °C and another one at about 205-210 °C. A heating rate of 4 °C s~(-1) was used in the temperature range from RT to 300°C. The additive dose, T_m-T_(STOP) thermal cleaning, initial rise, variable heating rate and computerized glow curve deconvolution methods have shown that the glow curve is a superposition of six peaks at 100, 130, 155, 175, 200 and 230 °C. The trapping parameters for the individual peaks have been calculated. The TL dose response of 130 and 200 °C peaks has a linear response. Zoisite is a candidate for a TL dosimeter because of its high sensitivity.