Explain the Silicon escape peak and sum peakSolutionSum peak

Explain the Silicon escape peak and sum peak.

Solution

Sum peaks are produced when the pulse processor cannot distinguish between two X-rays that arrive almost simultaneously. Instead of recording two X-rays with either the same or different energies, one X-ray with energy equal to the sum of the energies of the two incoming X-rays is recorded and plotted in the spectrum.

Escape peaks are produced when instead of all of the energy of an incoming X-ray being converted to electron-hole pairs, a Si K X-ray is generated from the silicon detector crystal. The energy measured for the incoming X-ray is reduced by the magnitude of the Si K X-ray, i.e. 1.74 keV, and an escape peak is detected in the ED spectrum. Less than 2% of incoming X-rays will fluoresce Si K X-rays, so escape peaks form minor peaks located at an energy 1.74 keV less than the energy of related major peaks in the spectrum.