A Method of Calibration for Measurement of Low Level Tritium in Environmental Water using a Liquid Scintillation Counter

When low levels of tritium are measured in water, quantifying and removing the background reading caused by other influences is very important. A liquid scintillation counter (LSC) and tritium-free water are most commonly used for measuring tritium and estimating the background caused by various sources. Tritium-free water is difficult to obtain and maintain, and developing a method for estimating the background without using tritium-free water is an important contribution. This study establishes such a method using a tritium enrichment operation on tritiated water samples which have several concentration levels. Because the value measured by the LSC is composed of the tritium signal and the background, an enrichment operation will only increase the tritium radiation signal. On this premise, tritiated water samples with several levels of tritium activity were enriched and used to quantify the background statistically.