Page 198 - Radiation Safety
P. 198
l Spontaneous disintegration of nuclides – which have unstable
number of n and p
l Emit ionising radiation (alpha, beta, gamma, etc.)
e.g. 140 Ba → 140 La → 140 Ce
(T 1/2 = 12.8 d, 40.3 h, emit beta & gamma)
l Activity - Disintegration rate
-1
S.I. Units: Becquerel (Bq), 1 Bq = 1 dps (s )
10
old units: Curie (Ci), 1 Ci=3.7 x 10 Bq
l Specific activity - activity per unit mass (Bq/g)
34
