Quantification of Olivine Using Fe Lα in Electron Probe Microanalysis (EPMA)

Area of Science:

• Geochemistry
• Materials Science
• Analytical Chemistry

Background:

• Quantifying first-series transition metal Lα X-rays is challenging due to absorption and chemical bonding variations.
• Existing methods struggle with accurate analysis when fluorescence yields change with chemical state.

Purpose of the Study:

• To develop a reliable method for quantifying iron Lα X-rays in olivine solid solutions.
• To address the impact of varying mass absorption coefficients and fluorescence yields on X-ray quantification.

Main Methods:

• Measured compound mass absorption coefficients for Fe Lα in the Forsterite-Fayalite solid solution series.
• Calculated mass absorption coefficients for Fe Lα absorbed by Fe.
• Corrected for discrepancies attributed to varying partial fluorescence yields.

Main Results:

• Systematic variations in mass absorption coefficients were observed across the olivine series.
• A good agreement between calculated and measured k-ratios was achieved after applying corrections.
• The developed method enables quantification of unknown k-ratios.

Conclusions:

• Modified matrix correction routines are necessary to account for different mass absorption coefficients and fluorescence yields.
• The study provides a robust method for accurate X-ray quantification in complex matrices.
• This approach enhances the reliability of transition metal analysis in geological and material samples.