Mistakes Encountered During Automatic Peak Identification in Low Beam Energy X-Ray Microanalysis
Dale E. Newbury
Automated peak identification in electron beam excited x-ray microanalysis with energy dispersive x-ray spectrometry is subject to occasional mistakes even on well separated, high intensity peaks arising from major constituents. The problem is exacerbated when analysis conditions are restricted to operation in the low beam energy scanning electron microscopy regime where the incident beam energy is 5 keV or less. These low beam energy microanalysis conditions force the analyst to use low fluorescence yield L-shell and M-shell peaks rather than higher yield K-shell and L-shell typically selected for elements of intermediate and high atomic number under conventional high beam energy (> 10 keV) conditions. Particular problems arise because of the effect of the EDS measurement process to convolve the closely spaced La-Lb and Ma-Mb peaks resulting in peak shifts of 30 eV or more that result in mistaken identifications. An extensive list of problem situations encountered in low beam energy microanalysis is presented based upon observed peak identification errors as well as likely combinations based upon proximity in peak energy.
energy dispersive x-ray spectrometry, peak fitting, peak identification, qualitative analysis, scanning electron microscopy, x-ray microanalysis