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Radioactivity is a random event which can only be adequately
described using statistics
•
Activity:
total number of disintegrations (decays) per unit time - SI
unit is the Becquerel (Bq) - nuclear transformation per second –
(Curie (Ci) activity of 1 gr of Ra-226)
•
Activity
→
A(t) =
l
N(t)
where N(t) is the number of radioactive nuclei at time t
•
Decay constant
l
→
characteristic parameter that describes how
fast a particular nucleus transforms (probability of disintegration per
unit time)
Activity
1 Ci = 37 x 10
9
Bq = 37 GBq