Processing of x-ray and electron spectra

A spectrum is a linear compilation of the output data, i.e signal intensity as a function of wavelength or energy, from an X-ray or electron energy loss spectrometer. In the earliest forms of the instrumentation the spectra existed only as traces on an oscilloscope or as the output plot of a chart recorder, and the operations that could be performed on them were therefore restricted to the identification of major features, and to manipulations that could be performed manually or graphically, such as estimating a background or integrating the area beneath a peak. In current instrumentation the spectrum is stored digitally in the memory of a computer. Since the data forming the spectral set can now be examined at will and transformed mathematically in any desired manner the spectrum can be processed to yield additional types of information. This paper will examine how spectral processing must be applied to obtain data from the X-ray and electron energy loss spectra generated from thin foils in the analytical electron microscope.