The unit of radioactivity adopted by the International System of Units (SI) is becquerel (Bq). This unit corresponds to the transformation of a nucleus with emission of ionizing radiation. This is called disintegration.
Bq = the number of decays of one nucleus per second.
The other unit, still in use, is the curie (Ci) which corresponds to the number of nuclei that disintegrate in one gram of radium 226 per second (old system).
1 Ci = 3.7 x 1010 Bq1 Bq ≈ 27 pCi | 1 Ci ≈ 37 GBq |
1 kBq ≈ 27 nCi | 1 mCi ≈ 37 MBq |
1 MBq ≈ 27 µCi | 1 µCi ≈ 37 kBq |
1 GBq ≈ 27 mCi | 1 nCi ≈ 37 Bq |
1 TBq ≈ 27 Ci | 1 pCi ≈ 37 mBq |
T = téra (1012) G = giga (109) M = méga (106) k = kilo (103) | m = milli (10-3) µ = micro (10-6) n = nano (10-9) p = pico (10-12) |