The peak produced by the detector is reasonably well described by Gaussian function (figure 1). Deviations from ideal Gaussian shape occur on the low energy side of the peak (figure 2). A second consequence of the incomplete charge collection phenomenon is the formation of a background shelf (figure 3) of count lost from the peak extending from the peak energy down to zero energy.


Figure 1: Theoretical Gaussian ditribution which describes an
EDS peak.


Figure 2: EDS spectrum of KCl shows 1. peak overlap and 2.
incomplete charge distrortion. The Cl K alpha and K beta peaks
are not resolved while K K alpha and K beta are nearly resolved.
The solid line is a Gaussian fit to the data points. The shaded
areas are the distrortions introduced by incomolete charge
collection.


Figure 3: EDS spectrum derived from 55 Fe radioactive source.
The background shelf is easily observed at energies below Mn K
alpha to the treshold energy 300 eV. The Si escape peaks from
Mn K alpha and K beta are noted.