ROLE OF QUENCHING ON ALPHA BETA SEPARATION IN LIQUID SCINTILLATION-COUNTING FOR SEVERAL HIGH-CAPACITY COCKTAILS/

The optimization of alpha/beta separation in liquid scintillation usin g pulse shape analysis is convenient for the simultaneous determinatio n of alpha and beta emitters in natural water and other samples, In th is work, alpha/beta separation was studied for different scintillant/v ial combinations and it was observed that both the optimum pulse shape discrimination level and the total interference value (that is, the s ummed relative interference between alpha and beta spectra) were depen dent on the sample quenching and independent of the scintillant/vial c ombination. These results provide a simple method for modifying the co unting configuration, such as a change in the cocktail, vial or sample characteristics, without the need to perform exhaustive parameter opt imizations, Also, it was observed that, for our counting conditions, t he combination of Ultima Gold AB scintillation cocktail with Zinsser l ow diffusion vials presented the lowest total interference, namely 0.9 4 +/- 0.28%, which is insignificant for the counting of environmental samples.