MAKING THE WATER SAMPLE-SCINTILLATOR RATIO OPTIMUM

THE liquid scintillation technique has achieved considerable popularity as a radioassay method for tritiated water because it combines ease of sample preparation with adequate counting efficiency. However, for low specific activity samples, i.e. samples producing a count approaching that of back-ground, counting times become long and the advantages of the technique become marginal. The purpose of this paper is to describe a method of scintillator- sample preparation that increases scintillator performance resulting in a substantial decrease in counting time for low specific activity samples. This is accomplished in two ways: (a) making the water sample-scintillating solution ratio optimum, and (b) deoxygenating the scintillating solution. In general, the techniques described here can be applied in the radioassay of water soluble radioisotopes other than tritium