Progress of Cryogenics and Isotopes Separation , ISSN: 1582-2575
2005, Volume 8, Issue 15+16

Direct Liquid Scintillation Measurement Applied to Environmental Water Sample

Abstract

The general decreasing trend of tritium level in the environment makes the use of the direct liquid scintillation method difficult. In this paper are presented experiments, which were performed in our laboratory to establish the routine procedure for tritium concentration determination in the environmental water samples by liquid scintillation counting (LSC). A low-level liquid scintillation spectrometer Quantulus 1220 is used in this work. The methods applied to determine counting efficiency are as follow: Spectral Quench Parameter of External Standard Method and Internal Standard Method. A comparison between dilution factors of heavy water samples, calculated both for D/(D+H)% concentration and tritium activity measured by the two methods, is discussed in the paper. The two standard recommendations that specify a method for determining tritium concentration in water sample by LSC have been investigated and the conclusions are shown. We decide to apply ISO method, and internal standard method for efficiency determination, for our routine procedure. Even if the uncertainty of the method is high, and even if tritium concentrations in the environment continue to decrease, the direct measurement of tritium concentration in water sample can still be a more rapid and cheaper measurement method for environment.