# Curie (unit)

Physical unit
Unit name curie
Unit symbol ${\ displaystyle \ mathrm {Ci}}$
Physical quantity (s) activity
Formula symbol ${\ displaystyle A}$
dimension ${\ displaystyle {\ mathsf {T ^ {- 1}}}}$
In SI units ${\ displaystyle \ mathrm {1 \; Ci = 37 \, GBq}}$ ${\ displaystyle \ mathrm {= 3 {,} 7 \ ​​cdot 10 ^ {10} \; s ^ {- 1}}}$
Named after Marie and Pierre Curie
Derived from Activity of radium -226
See also: Becquerel

Curie is the obsolete unit of activity of a radioactive substance with the symbol Ci; it was used temporarily until 1985, when it was replaced by the SI unit Becquerel . Today it is only used in materials testing. 1 curie was originally defined as the activity of 1 g of radium -226, and later set to the approximately same value of 3.7 · 10 10  Becquerel (= 37 GBq).

The unit was named after Marie and Pierre Curie who, together with Antoine Henri Becquerel, received the Nobel Prize for the discovery of radioactivity in 1903 .