Developments of non-destructive quantification for trace elements in high-pressure run-products by proton beam

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This project aims to study and develop non-destructive quantitative analytical method of trace elements in high-pressure run-products by PIXE (proton-induced X-ray emission) method. We have developed : 1) a micro-proton beam line for high-pressure product analyses and sample chamber for microanalyses equipped with microscope, micro-driving stage, and two solid state detectors for light and heavy element analyses ; 2) analytical procedures for high-pressure run-products ; 3) quantification of trace elements in single fluid inclusions buried in mineral matrix. A 4 MeV proton micro-beam of 2 nA, 50 μm in size was obtained in the developed beam line by a new quadropole magnet. By using PIXE at the new beam line, high-pressure run-product, graphite-diamond mixtures and basaltic glasses maintained at 2000 C and 7.7 GPa, was analyzed. The graphite contained almost the elements derived from basaltic glass as interlayer impurities, indicating concentration of many elements in graphite under the high-pressure condition. Natural diamonds include usually graphite, so that analyses of the graphite can provide a chemical information of diamond-growth. In addition, trace elements ranged from 10 to 1000 μg/g in single fluid inclusions were determined with ±15 % relative precision by using the developed quantification. At the present measurements, a few μg/g elements were detected in the fluid inclusion with 200 μm in diameter, corresponding to several-picograms (〜10^<-12> g) detection of elements in inclusions.