Quantitative microanalysis using electron energy-loss spectrometry. I. Li and Be in oxides

Abstract

Electron energy-loss spectrometry enables the detection of Li and Be via the K ion- ization edges. However, the detection and quantification of these low energy edges present several problems, like low edge-to-background ratios, problems with background extrapolations, overlapping of edges and multiple scattering in case of thicker specimens. All these problems can be overcome by careful application of well known procedures: Spectra have to be recorded from very thin specimen regions (t/03BB 0.5) and subsequently deconvoluted by the Fourier-log-method. This procedure im- proves the background in front of the edges, so that the conventional A . E-r model can be used for background fitting without problems. The Li and Be K edges overlap with other edges e.g. the L23 edges of elements Mg to P and the M23 edges of the elements Ca to Cu. In such a situation quantita- tive analysis is only possible by a multiple-least-square fit with reference spectra and if experimentally determined partial cross-sections are used. The successful application of these methods is demon- strated for inorganic materials like phenacite, beryl, spodumene, Be-phosphate and Li-Cr-oxide. The quantification and detection limits for Li and Be in typical material science specimens are discussed.