Permanent radioactive decay

Permanent radioactive decay (l) - decay probability of each individual nucleus of an atom per unit of time, measured in units of inverse time measurement units (sec-1, min-1). To characterize the rate of decay (see Radioactivity) also use the half-life (T) and the average lifetime (t)that are associated with P. p. p. following ratios:
For each radioactive isotope λ has a certain value and varies widely. So, permanent radioactive decay of uranium U234 equal 8,80·10-14 sec-1, P32 -5,73·10-7 sec-1, polonium Ro214 - to 4.38·103 sec-1. If the radioactive isotope has several types of radioactivity, for example, along with alpha-decay beta-decay, the General P. p. p. equal to the sum of the partial decay constants: