90Sr determination in water samples using Čerenkov radiation

A procedure for the determination of 90Sr in environmental water samples using Čerenkov radiation and low-level liquid scintillation counter Quantulus 1220 was applied and optimized. Low diffusion polyethylene vials, high performance glass counting vials and low potassium borosilicate glass vilas of 20 ml volume (all from PerkinElmer) were used in order to examine their potential effect on counting process. The derived efficiencies were 45.86(9)%, and a minimum detectable activity of 0.32 Bq l−1 in a 20 ml polyethylene vial (20 ml water sample) has been achieved during 300 min of measurement. Environmental water samples might be colored and this will lead to color quenching, which one of the most important problems that affect Čerenkov is counting (Mosqueda et al., 2005). The sample channel ratio (SCR) method has been applied to correct this effect. The analytical procedures and measurement techniques were tested by participating in the IAEA-TEL-2015-03 world-wide proficiency test on determination of 90Sr in water sample.