If X-rays of a peak energy E1 are being measured, pulse coincidence can lead to a continuous band of overlapping pulses in the range E1 to 2E1, the so-called pulse pileup contiuum are accur (figure 1 and 2).


Figure 1: EDS spectrum of Mn excited by 15 keV electrons.
Pile-up peaks and pile-up continuum can be observed.


Figure 2: EDS spectrum of Si excited by 15 keV electrons.
Only small sum peak can be observed and the pile-up
continuum is not significant.