Solving the iron quantification problem in low-kV EPMA: An essential step toward improved analytical spatial resolution in electron probe microanalysis—Fe-sulfides
- 1 August 2022
- journal article
- research article
- Published by Mineralogical Society of America in American Mineralogist: Journal of Earth and Planetary Materials
- Vol. 107 (8), 1532-1544
- https://doi.org/10.2138/am-2022-8027
Abstract
The use of the field emission gun in scanning electron microscopy permits the imaging of submicrometer-size features. However, achieving sub-micrometer analytical spatial resolution in electron probe microanalysis (EPMA) requires both reducing the electron beam size and reducing the accelerating voltage to achieve the desired sub-micrometer interaction volume. The resulting quantification of the first-row transition metals at low accelerating voltage, i.e., below 7–8 kV, is problematic as the main characteristic X-ray lines (Kα) cannot be excited at these conditions. Furthermore, the use of the Lα and Lβ soft X-ray lines for quantification is complicated by bonding and self-absorption effects resulting in not-yet-determined mass absorption coefficients and hence in the failure of the traditional matrix correction procedure. We propose two methods to circumvent these low-kilovolt (low-kV) analysis limitations: using the non-traditional FeLℓ line and using universal calibration curves for the more traditional FeLα and Lβ lines. These methods were successfully applied to Fe-sulfide minerals showing accurate quantification results by EPMA at reduced kV, necessary for accurate quantification of sub-micrometer sulfide grains.Keywords
This publication has 26 references indexed in Scilit:
- Minimum detection limit and spatial resolution of thin-sample field-emission electron probe microanalysisUltramicroscopy, 2013
- Measurements of absolute L- and M-subshell x-ray production cross sections of Pb by electron impactJournal of Physics B: Atomic, Molecular and Optical Physics, 2013
- The nanoscale mineralogy of Fe,Ni sulfides in pristine and metamorphosed CM and CM/CI‐like chondrites: Tapping a petrogenetic recordMeteoritics & Planetary Science, 2013
- Trace analysis in EPMAIOP Conference Series: Materials Science and Engineering, 2012
- Development of wavelength-dispersive soft X-ray emission spectrometers for transmission electron microscopes--an introduction of valence electron spectroscopy for transmission electron microscopyJournal of Electron Microscopy, 2010
- Sulfide inclusion chemistry and carbon isotopes of African diamondsGeochimica et Cosmochimica Acta, 1995
- Quantitative Analysis of Homogeneous or Stratified Microvolumes Applying the Model “PAP”Published by Springer Science and Business Media LLC ,1991
- Empirical Correction Factors for the Electron Microanalysis of Silicates and OxidesThe Journal of Geology, 1968
- An Algorithm for Least-Squares Estimation of Nonlinear ParametersJournal of the Society for Industrial and Applied Mathematics, 1963
- Quantitative Analysis with the Electron Microanalyzer.Analytical Chemistry, 1963