Escape Peak
A peak resulting from incomplete deposition of the energy of an X-ray entering the energy dispersive X-ray spectrometer detector. This peak is produced when an incoming X-ray excites a silicon atom within the detector crystal, and the resulting Si K-a fluorescence X-ray exits the detector crystal. It occurs at the principal peak energy minus the energy of the Si K-a fluorescence X-ray (1.74 keV). The escape peak intensity is about 1 to 2 % of the parent peak.