Effects of Electron Beam on Structure and Physical Properties of Natural Colorless Topaz

Abstract

The purpose of this research was to investigate physical properties, configuration and color of topaz. Topazes were irradiated with electron beam linear accelerator at different dose from 40 to 180 MGy. The color of topaz was analyzed by UV-vis and it was shown that the color of topaz was becoming strong color with increased electron beam dose. Crystal structure and function group of topaz were characterized by X- ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The results showed that the topaz has orthorhombic structure and no other crystalline. After irradiated, topaz released OH indicating higher crystallinity of topaz and this was confirmed with the results of electron spin resonance (ESR). Electron beam dose response of topaz was investigated. ESR results showed that the Al3+ ion was substituted in Si4+ site and Ti3+ impurity in Al4+ site and this result corresponds to the results of FTIR. The experiment result indicated that electron beam could be making defect on crystal structure and color enhancement of topaz.