ionization of the analyte element in a sample by characteristic radiation from other elements in the sample resulting in an enhancement of the signal measured.
Source:
PAC, 1980, 52, 2541. 'Nomenclature, Symbols, Units and their Usage in Spectrochemical Analysis—IV X-Ray Emission Spectroscopy' on page 2547 (https://doi.org/10.1351/pac198052112541)