Nuclear Radiation as probe to investigate some of the physical properties of Willemite

A radiation is frequently used to explore the physical properties of materials. Here, we investigated the thermoluminescence (T L) and electron paramagnetic resonance (EPR) properties of the willemite, a silicate mineral, under γ-irradiation. Electron irradiation is also under way. Willemite, of chemical formula Zn2SiO4, is a silicate mineral of the Olivine Group, together with fayalite (Fe2SiO4), forsterite (Mg2SIO4) and phenakite (Be2SiO4). A sample of willemite of mexican origin purchased from a local stone dealer is a bunch of about 35-40 small crystals of size 2-3 mm, glued on another mineral called limonite. X ray fluorescence analysis indicated besides SiO2 and Zn O, basic components of willemite, Al2O3 and Fe2O3 as main impurities in both minerals. This analysis has shown that limonite is a solid solution of willemite and fayalite. Willemite presented 160, 230 and 320 0C T L peaks that irradiated with gamma-rays grows in intensity with the radiation dose up to about 2000-2500 Gy, saturating beyond. The limonite has only 160 and 270 0C peaks; they also grow in intensity with radiation dose up to about 5000 Gy. These results indicate that these minerals can be used for high dose dosimetry. Since limonite has large concentration of iron (about 11,1 weight %) its EPR spectrum dominated by a strong signal at g = 2,0. But willemite presented signals due to peroxy-canter that grows with radiation dose. Effects of electron irradiation will be presented at the meeting