Refinement of major- and minor-element PIXE analysis of rocks and minerals

An attempt has been made to assess the accuracy of the particle-induced X-ray emission (PIXE) fundamental parameters with standards approach to quantifying major- and minor-element constituents of silicate glasses and minerals. A deviation from linearity at low energies in the channel-energy calibration relationship was identified as a source of undesired residues in GUPIX-fitting. A correction for this effect was developed using a general-purpose spectrum fitting program and was incorporated in GUPIX. The PIXE spectra of sixteen well-characterized electron microprobe standards were then processed. Complementary electron probe micro-analysis (EPMA) measurements were used to support the comparison of the PIXE results with previous characterizations. Major element concentrations were found to differ on average from literature values as follows: SiO2 (-0.28 +/- 0.12%), Al2O3 (0.72 +/- 0.74%), MgO (0.11 +/- 0.63%), Na2O (-2.6 +/- 1.2%), K2O (1.1 +/- 0.7%), Cab (-0.35 +/- 0.37%), TiO2 (2.5 +/- 1.9%), MnO (0.8 +/- 4.7%), FeO (0.98 +/- 0.93%). These results indicate that major and minor elemental analysis can be achieved with high accuracy using the present Guelph micro-PIXE setup. (C) 2015 Elsevier B.V. All rights reserved.