The evaluation of uncertainty in low-level LSC measurements of water samples

The uncertainty in measurements of gross α and β activities in water samples by liquid scintillation counting with α/β discrimination has been evaluated considering the problems typical of low-level measurements of environmental samples. The use of a pulse shape analysis device to discriminate α and β events introduces a correlation between some of the input quantities, and it has to be considered. Main contributors to total uncertainty have been assessed by specifically designed experimental tests. Results have been fully examined and discussed.