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

•Precision calibration of PIXE system for quantifying major element constituents in silicates.•Use of new mass attenuation coefficient database in GUPIX fundamental parameters analysis.•Identification of and correction for an energy calibration non-linearity found in SDD spectra.•PIXE quantification of major and minor constituents to within single percent accuracy.•Results validated by previous electron microprobe and chemical analyses. 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%), CaO (−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.