Publications Details
A controlled dispersion parallel wavelength x-ray spectrometer for electron microscopy
This paper describes a new technique for the detection of x-rays in electron column instruments used in microanalysis. In electron column instruments, the point source of x-rays is produced by the interaction of a focused electron beam with the sample. Neither of the conventional methods, wavelength dispersive (WDS) nor energy dispersive (EDS) based spectrometry, is optimized for low Z element quantitative analysis. In WDS applications, where the analyte elements are Be through P, chemical effects complicate the x-ray measurement process. Peak positions and shapes are altered, sometimes very strongly, by the electron configurations of the analyte atoms and neighboring atoms. In these cases, the ideal spectrometer would profile the peak and some small amount of continuum on either side of the peak such that an accurate peak area could be calculated. Present WDS spectrometers are serial in nature and cannot directly measure peak areas, often causing errors in the determination of light element concentrations. Bastin and co-workers have developed an elegant method to provide accurate area determinations, using the serial spectrometer, by a three point procedure. The parallel wavelength dispersive spectrometer (PWDS) we propose here is ideally suited for those applications.