1. Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, China
2. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
3. University of South China, Hengyang,Hunan 421001, China
Abstract：Aiming at the tritiated methane as the gas reference source for the calibration of airborne tritium monitor, a method for measuring its volume radioactivity is proposed. Tritiated methane is transformed into tritiated water by catalytic oxidation combustion furnace. Tritiated water is collected by two-stage series bubbler, and measured by liquid scintillation counter.Finally, the volume activity of tritiated methane is determined, and the uncertainty is analyzed.Implementing the above method, the volume radioactivity of the tritiated methane in lab and its expanded uncertainty are determined to be 17.4MBq/m3and 6.4% (k=2) separately, which meet the requirements for gaseous reference source according to GBT 30150-2013.The calibration experiment for a commercial airborne tritium monitor is conducted with the tritiated methane in lab, in which the calibration factor is 0.88. It indicates that the proposed method can provide a practical and credible technical basis for airborne tritium monitor calibration.
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2022, Vol. 43 
