Detection of Lead (Pb) in Rubies
21 September 2012
A comprehensive ion beam analysis center, equipped with a 1.7-MV “Tandetron” tandem accelerator, has been established at Chiang Mai University, Thailand. The beam line is currently able to perform several ion beam analysis techniques with assistance of commercial and self-developed softwares for real-time characterization of various materials. Among several interesting applications, PIXE and IL techniques are applied to study gemstones. PIXE is powerful, fast and relatively simple analytical technique that can be used to identify and quantify trace elements. Up to 40 elements can be quantified simultaneously in samples weighing only a few milligrams. The technique bases on the evaluation of the emission of characteristic x-rays from atoms of each trace element induced by proton beam. Additionally, the beam also induces a detectable luminescence from the sample, which is called IL technique. IL, from ionoluminescence, is potentially a highly sensitive method for measuring optically active impurities and defects in samples.
Fig. 1. PIXE spectra of untreated rubies and rubies treated by conventional heat treatment (Paw Kaw) and lead-glass filled treatment (Paw Mai). .....read more