moderator

https://doi.org/10.1351/goldbook.M03961
A material used to reduce the @N04116@ energy by @S05487@ without appreciable @C00796@.
Source:
PAC, 1994, 66, 2513. (Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)) on page 2522 [Terms] [Paper]