Reliability of the low level 3H activity determined by liquid scintillation measurement

Reliability of low level T activity determined by the liquid scintillation counting has been studied in the case when a large amount of water sample is incorporated with two types of emulsion scintillators; first group is scintillators which have three distinct regions of the sample condition when increasing the amount of water sample, and second group is those which form a miscible solution up to about 50% water content. In a large water content, the error of the T activity measured with the first group scintillator becomes, in many cases, very larger than that with the second group scintillator. This is attributable to the reduction of liquid scintillation pulse height distribution for the gel sample, depending highly upon temperature. The counting efficiency of the sample prepared by the second group scintillator is less affected by the variation in temperature. (orig.)