Resolution 7 of the 12th CGPM (1964)


The 12th Conférence Générale des Poids et Mesures (CGPM),

considering that the curie has been used for a long time in many countries as unit of activity for radionuclides,

recognizing that in the Système International d'Unités (SI), the unit of this activity is the second to the power of minus one (s–1),

accepts that the curie be still retained, outside SI, as unit of activity, with the value 3.7 ´ 1010 s–1. The symbol for this unit is Ci.

DOI : 10.59161/CGPM1964RES7E

The reader should note that the official version of this Resolution is the French text


The name "becquerel" (Bq) was adopted by the 15th CGPM in 1975 (Resolution 8) for the SI unit of activity: 1 Ci = 3.7 x 1010 Bq.

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