In Si(Li) detectors ecape peaks occurring 1.74 keV below each 'true' peak. Escape peaks are small (up to 1% of parent peak height) and its desirable that they should be removed from the spectrum for quantitative analysis. Figure 2 show EDS spectrum from 55 Fe radioactive source with escape peaks and figure 3 EDS spectrum of Mn.
Figure 1: 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.
Figure 1: EDS spectrum of Mn excited by 20 keV electrons.
As compared to Figure 1, the continuum spectrum makes the
observation of the incomplete charge collection difficult except
near the peak. The background
shelf is obscured in this
spectrum but it still present.