- Radiation from any source other than the one it is desired to detect or measure.
Orange Book, 2nd ed., p. 213 (http://media.iupac.org/publications/analytical_compendium/)
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2516 (https://doi.org/10.1351/pac199466122513)
- Radiation which originates from the source and reaches the detector when no analyte is present.
PAC, 1985, 57, 1453. 'Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation sources (Recommendations 1985)' on page 1462 (https://doi.org/10.1351/pac198557101453)