chapter  7
17 Pages

EELS imaging

WithRik Brydson

One approach to Electron Energy Loss Spectroscopy (EELS) imaging, in widespread use for the characterization of both biological and materials science samples in the Transmission Electron Microscopy (TEM), is to employ a magnetic prism spectrometer and an energy selection slit to filter the spectrum of transmitted electron energies normally used to form conventional TEM images and diffraction patterns. To record a conventional EELS spectrum, the energy selecting slit is removed and the filter operated in spectrum mode, the spectrum incident on the detector is spread out in the non-dispersion direction and spectrum profiles obtained by lateral integration over the detector pixels. If the element of interest is present at low levels, the three-window method often produces noisy images and artefacts in elemental maps. In particular, the mapping of elemental distributions in microstructures has been discussed in detail including the quantification of the intensity values in such images.