Curie
From Wikipedia, the free encyclopedia
For other uses, see Curie (disambiguation).
The curie (symbol Ci) is a non-SI unit of radioactivity, named after Marie and Pierre Curie.[1][2] It is defined as
Its continued use is discouraged.[3]
One curie is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the Curies.
The SI derived unit of radioactivity is the becquerel (Bq), which equates to one decay per second. Therefore:
- 1 Ci = 3.7 × 1010 Bq = 37 GBq
and
- 1 Bq ≅ 2.703 × 10−11 Ci
Another commonly used measure of radioactivity is the microcurie:
- 1 μCi = 3.7 × 104 disintegrations per second = 2.22 × 106 disintegrations per minute
A radiotherapy machine may have roughly 1000 Ci of a radioisotope such as caesium-137 or cobalt-60. This quantity of radioactivity can produce serious health effects with only a few minutes of close-range, un-shielded exposure.
The typical human body contains roughly 0.1 μCi of naturally occurring potassium-40.
[edit] References
- ^ curie - Britannica Online Encyclopedia
- ^ Paul W. Frame. "How the Curie Came to Be". http://www.orau.org/ptp/articlesstories/thecurie.htm. Retrieved 2008-04-30.
- ^ Nist Special Publication 811, paragraph 5.2.
