becquerel

https://doi.org/10.1351/goldbook.B00624
SI derived unit of radioactivity equal to one disintegration per second; admitted for reasons of safeguarding human health, symbol: Bq.
Sources:
Green Book, 2nd ed., p. 72 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2516 (https://doi.org/10.1351/pac199466122513)
PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 963 (https://doi.org/10.1351/pac199668040957)