Shape of Xray Peak in EDS Measurements  Practical Electron Microscopy and Database   An Online Book  

Microanalysis  EM Book http://www.globalsino.com/EM/  


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The EDS measurement with Si (silicon) detectors is highly linear when calibrated over the energy range from 1 keV to 10 keV. In general, for Xray peaks above 1 keV, it is sufficient to evaluate the Xray intensities by considering the measured Xray peaks as a Gaussian distribution for a single photon energy. In this case, the intensity as a function of energy is given by (see Figure 1755),
In fact, most software available on commercial EDS systems uses the Gaussian approximation to describe the observed shape of an Xray peak. Figure 1755. Gaussian distribution of the shape of Xray peaks. According to the Hyperment function, the asymmetry of the Xray peaks measured from the photondetector interactions can be theoretically obtained by adding two analytical expressions S(E) and D(E) to describe the spectroscopic features. [1] Therefore, the measured Xray line shape P(E) as a function of the analyzed photon energy E, can be given by,
[1] J. L. Campbell, A. Perujo and B. M. Millman, Analytic description of Si(Li) spectral lineshapes due to monoenergetic photons, XRay Spectrometry, 16(5), 195–201, 1987.


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