scintillators

https://doi.org/10.1351/goldbook.S05507
Materials used for the measurement of radioactivity, by recording the radioluminescence. They contain compounds (chromophores) which combine a high fluorescence quantum efficiency, a short fluorescence lifetime, and a high solubility. These compounds are employed as solutes in aromatic liquids and polymers to form organic liquid and plastic scintillators, respectively.
Sources:
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2525 (https://doi.org/10.1351/pac199466122513)
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2272 (https://doi.org/10.1351/pac199668122223)