Deconvolution in EDS Analysis
- Practical Electron Microscopy and Database -
- An Online Book -
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For EDS analysis, it is necessary to highlight that except for the random errors from counting statistics, some factors, however, will contribute systematic errors. Those factors are mainly:
Deconvolution can only be done by optimizing the whole line series. However, deconvolution is not necessary if there is no line overlaps in the spectrum.
The deconvolution in EDS analysis can be tricky mainly because:
Figure 2359a shows two schematic spectra obtained from two EDS detectors with energy resolutions at Mn Kα 120 eV and 130 eV, respectively. It is clear that higher spectrum peak can be obtained with better resolution. Consequently, the higher peak improves the peak-to-background ratio and facilitates the spectrum deconvolution.
Figure 2359b shows the deconvolution of an EDX spectrum with peak overlaps, taken from a material that contains O, Ti, N, and C elements.
Figure 2359b. Deconvolution of an EDX spectrum with peak overlaps. 
Table 2359 shows the calculated (in black) and experimental (in red) peaks of samples with pure sulfur, pure molybdenum, 1 wt% S + 99 wt% Mo, and 15 wt% S + 85 wt% Mo. The main consideration about the match between calculated and experimental curves are the portion of 1.2 times of the full width at half maximum (FWHM) of the peaks. For the sample with 1 wt% S + 99 wt% Mo, the maximum of the calculated peak does not match the maximum of the experimental one since the calculated curve slightly shifts to the left of the experimental curve, while the two peaks of the calculated and experimental curves match each other better when 1 wt% S is considered. For the sample with 15 wt% S + 85 wt% Mo, the shapes of the calculated and experimental curves math each other when 15 wt% S is considered.
J. Berlin, T. Salge, M. Falke, and D. Goran, Recent Advances in EDS and EBSD Technology: Revolutionizing the Chemical Analysis of Chondritic Meteorites at the Micro- and Nanometer Scale, 42nd Lunar and Planetary Science Conference, 2723, (2011).