Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course (BPTC) on Nuclear Safety
Absorbed dose (D) x QF = Dose equivalent (H)
1 gray gamma x 1 = 1 sievert
1 gray beta x 1 = 1 sievert
1 gray neutron x 10 = 10 sievert
1 gray alpha x 20 = 20 sievert
The SI unit of radioactivity is the bequerel (Bq), named after its discoverer, Henri
Bequerel, and is defined as one nuclear disintegration per second (dps). Disintegration
usually involves the emission of one or more charged particles (α or β), which are
usually, but not always, accompanied by one or more gamma rays. Compared with the
curie, the bequerel is extremely small, so in practice is it convenient to adopt the usual
multiples:
1 bequerel (Bq) = 1 disintegration/second (dps)
1 kilobequerel (kBq) = 10 3
Bq = 10 3
dps
1 megabequerel (MBq) = 10 6
Bq = 10 6
dps
1 gigabequerel (GBq) = 10 9
Bq = 10 9
dps
1 terabequerel (TBq) = 10 12
Bq = 10 12
dps
1 petabequerel (PBq) = 10 15
Bq = 10 15
dps
Until quite recently, the unit of radioactivity was the curie (Ci). Along with its various
submultiples: i.e., millicurie, mCi (10 -3
); microcurie, µCi (10 -6
); nanocurie, nCi (10 -9
);
picocurie, pCi (10 -12
), the curie was originally related to the activity of one gram of
radium, but the definition was later standardized as 3.7x10 10
disintegrations per second.
The relationship between the old and new units is shown below:
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