生物组织中自由水氚测量的不确定度评定

his paper evaluates the uncertainty of tissue free water tritium determination through the calculation model. The GUM method is used to evaluate the uncertainty of the detection method. The uncertainty components mainly includes the uncertainty of the moisture content of the sample, the uncertainty of the net counting rate of the sample measurement, the uncertainty of the detection efficiency of the method and the uncertainty of weight of the sample. After the calculation of each component, it is found that the relative standard uncertainty of the moisture content of the sample and the relative standard uncertainty of measuring the sample weight are relatively small, which can be ignored. The relative uncertainty of method efficiency is mainly affected by the activity of the standard source added to the efficiency calibration and the uncertainty of the standard source itself. The net counting rate of the sample is the most affected by the uncertainty of the detection method. When the sample radioactive specific activity is close to the background level, the uncertainty of the detection method is mainly contributed by the uncertainty caused by the net counting rate of the sample.