Detection efficiency of plastic scintillator for gaseous tritium sampling and measurement system

To develop a gaseous tritium sampling and measurement system detection efficiency of plastic scintillator was examined. The advantage of using the plastic scintillator would be not expected to produce waste of liquid scintillator. Following the process of catalytic oxidization in the tritiated gas sampling system, a combined nebulizer and denuder tube was considered instead of a moisture absorber. The scintillation produced by exposure beta particle of tritium in the recovered water to the plastic scintillator was detected with a photomultiplier tube. The sensitivity to measure the tritium concentration in water was experimentally obtained. Then good linear relationships between the count rate and radioactivity were observed. Also the sensitivity to tritium and high-energy beta decay nuclides such as 14C and 90Sr in water were compared. The detection efficiency depended on the range of beta particle and the surface area of the plastic scintillator attached to the solution. Improving the effective surface area of the plastic scintillator would lead to a useful monitor.