Professional Tools for High Accuracy Low Z Element Analysis
Probe Software applications, Probe for EPMA and CalcImage, provide the state-of-the-art in quantitative low Z element (Z < 11) analysis methods. Whether you need major element or trace element analysis of light elements we have the necessary tools.
- Area Peak Factors (APFs), using both specified and compound methods
- Empirically derived Mass Absorption Coefficients (MACs)
- Advanced background fitting methods (exponential, polynomial, multi-point, etc.)
- Time Dependent Intensity (TDI) corrections for carbon contamination/ion migration
- Advanced phi/rho-z matrix corrections (PAP/XPP)
- Quantitative interference corrections for trace low Z elements
- Quantitative X-Ray mapping for low Z elements
Area Peak Factors for Peak Shape/Shift Corrections
Area Peak Factors (APFs) automatically compensate for differences in the peak to integrated intensities between standards and unknowns due to peak shape/shift changes.
Specified Area Peak Factors
Specified APFs are peak shape measurements made using a specified primary standard and a specified unknown sample and are the most accurate method to correct for changes in peak shape with low Z elements. However, these specified APFs cannot always be applied to other materials with different bonding characteristics.
Compound Area Peak Factors
Compound APFs are “compounded” from measurements of binary light element materials (MgO, SiO2, SiC, AL2O3, Fe2O3, Fe3C, etc.), which are then weighted by the concentration of each element’s contribution to the peak shape. This method allows for quick and accurate low Z element analysis by leveraging an extensive database of existing peak shape measurements, by experts in the field of microanalysis.
Probe Software utilizes published APFs from Bastin, Pouchou and Donovan, referenced to the original primary standards or utilize them automatically as re-normalized APFs, referenced to your own primary standards.
Empirical Mass Absorption Coefficients
Empirically measured mass absorption coefficients (MACs) are required for most low Z element analyses for best accuracy.
Probe for EPMA contains a large database of empirically measured mass absorption coefficients based on multi-voltage measurements from Pouchou, Bastin and Donovan.
Utilizing a suitable application such as BadgerFilm or XMAC one can also empirically determine their own mass absorption coefficients on arbitrary compounds, using the multi-voltage method of Pouchou, and enter them into the Probe for EPMA/CalcImage empirical MAC database for subsequent use for high accuracy low Z element quantitative analyses.
Excess Oxygen from Measured Oxygen or Ferric/Ferrous Charge Balance
Utilize Probe for EPMA (for point analyses) and/or CalcImage (for quantitative x-ray maps) to calculate excess oxygen from measured oxygen, based on cation/oxygen ratios or determine excess oxygen from ferric iron, based on mineral charge balance (Droop, 1987).
Quantitatively determine excess (or deficient) oxygen from ferric or halogen equivalence. Similarly, one can determine water by excess oxygen and stoichiometry to hydrogen from measured oxygen and cation stoichiometry.
Perform Time Dependent Intensity (TDI) Corrections
Both Probe for EPMA and CalcImage can automatically perform time dependent intensity (TDI) corrections for both point analyses and quantitative x-ray maps and correct for carbon contamination, ion migration and other beam sensitivity artifacts.
No longer be limited to reducing beam current and/or increasing beam diameter with your beam sensitive samples. The TDI acquisition methods and corrections document and compensate for such effects automatically. Now one can analyze micron sized phases, e.g., melt inclusions, with confidence.
