actinometer

https://doi.org/10.1351/goldbook.A00087
A chemical system or physical device which determines the number of @P04627@ in a beam integrally or per unit time. This name is commonly applied to devices used in the @UT07492@ and @VT07496@ @W06659@ ranges. For example, solutions of iron(III) oxalate can be used as a @C01016@, while bolometers, thermopiles, and photodiodes are physical devices giving a @R05189@ that can be correlated to the number of photons detected.
See also:
chemical actinometer
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2227 [Terms] [Paper]