Fourier deconvolution of electron energy-loss spectra

Abstract

Electron energy-loss spectroscopy (e.e.l.s.) performed with an electron microscope can be used to obtain plasmon spectra, near-edge fine structure and extended electron energy-loss fine structure (ex.e.l.f.s.), as well as to do chemical analysis on truly microscopic samples. However, the very strength of the electron-electron interaction gives rise to significant and sometimes predominant plural scattering effects. To obtain consistent and reliable estimates of the single scattering distributions these effects must be accounted for. In this paper, two Fourier-transform deconvolution methods of removing plural scattering from electronenergy-loss spectra and their implementation on a microcomputer, are discussed. Their relative advantages and limitations are considered together with examples of artefacts that may arise in both plasmon and core-loss spectra. As a result of deconvolution the sensitivity and accuracy of core-elemental analysis is enhanced but, more importantly, it is possible to obtain reproducible near-edge structure and plasmon spectra from relatively thick samples that would otherwise not be suitable for investigation by means of e.e.l.s.