Utilization of a high-speed x-ray analysis system with a SEM

Abstract

A high speed x-ray analysis system has been developed using a scanning electron microscope(SEM) with an energy dispersive spectrometer(EDS). In this system digital beam control is combined with other microscope control from the EDS system. The EDS system has specially designed software to allow a full quantitative analysis to be performed in fractions of a second. This allows several novel forms of analysis, such as fully quantitative x-ray maps and analysis of non-homogeneous specimens. Due to the high speed of the software, conventional intensity x-ray maps are made into quantitative maps, during the process of acquiring them. Non-homogeneous samples are analysed by randomly positioning the beam on the sample, doing a full analysis, then moving the beam to a new point. When this procedure is repeated many times, the specimen is sampled in a way to produce a true average analysis.Background and peak overlap corrections must be applied to obtain net elemental intensities from the EDS spectrum. It is impractical to store a full spectrum at each analysis location of the map, so the corrections must be made “on the fly”. Normally it requires tens of seconds to obtain net elemental intensities and to convert these to concentrations with a ZAF technique. In this work these times have been reduced to 100 milliseconds by the use of optimized programming of the various correction procedures.