Electron-excited x-ray spectrum image (XSI) elemental mapping can now be performed in remarkably short time, 30
seconds or less, with the silicon drift detector energy dispersive x-ray spectrometer (SDD-EDS). Major constituents
(concentration, C > 0.1 mass fraction) and minor constituents (0.01 < C < 0.1) can be mapped with such short duration
scans, and trace constituents (C < 0.01) can often be mapped in 300 second scans. Constraints imposed by the older
Si(Li)-EDS are greatly reduced with the new SDD-EDS technology, enlarging the range of application of elemental
mapping. While high speed mapping has numerous applications, mapping times up to 30 minutes duration are useful for
higher pixel density that can reveal unexpected fine spatial details, finer than the x-ray interaction volume appears to
permit. Longer duration SDD-EDS mapping enables recording a deeper x-ray gray scale, permitting compositional
contrast to be observed at much lower values for major, minor, and trace constituents.
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