Erroneous Peaks in Energy Dispersive X-Ray Spectra

Extract

The necessary first step in using an x-ray fluorescence spectrometer for quantitative analysis is to obtain the intensities for the various elements. With a wavelength dispersive system this usually requires simply setting the crystal to the proper angle (and possibly adjusting the pulse height selector) and making a dead-time correction. With the energy dispersive x-ray fluorescence analyzer it is necessary to take into account the presence of erroneous peaks in the spectrum, to obtain true intensity values.

False peaks due to diffraction of white tube radiation from the sample can usually be shifted to portions of the energy spectrum where they do not interfere with emission lines of interest by selection of the proper tube-sample-detector geometry. Modern amplifier design provides a built – in dead time correction and greatly reduces the effects of pulse-pile-up, although the latter phenomenon will still produce small peaks at exact multiples of major peaks.