The dynamics of the detection of 226Ra in water by scintillation counting in nonequilibrium conditions

The conventional methods for the 226Ra determination by liquid scintillation counting require to attain secular equilibrium between 226Ra and 222Rn prior to the counting. This study describes a method that allows the immediate counting of a sample after the dissolution of Ba(Ra)SO4 in EDTA. This results from a detailed modelling of the activity of the parent 226Ra and its daughters in both the aqueous and organic scintillator phases. This methodology was tested on standard solutions of 226Ra showing promising results.