Abstract：Based on the Bragg-Gray cavity theory of measurements of air kerma for gamma ray, the air kerma rate is measured by using graphite cavity ionization chamber, and the mathematical model of measurement is established. The effect of influence quantities and its correction are taken into account during the process of uncertainty analysis for the measurement of air kerma. The correction factors and its uncertainty are gotten by using the methods of measurement and Monte Carlo simulation. The expanded uncertainty of gamma ray air kerma is about 0.5%, and that the mainly contribution of the uncertainty of gamma ray air kerma are come from the uncertainty of wall correction and average ionization power, so it is necessary to carry out the corresponding research, in order to improve the uncertainty level of the air kerma rate measurement.
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2016, Vol. 37 
