Dynamic calibration method for detection efficiency of radioactive source
It is difficult to produce the radioactive standard gas source such as 133Xe, which makes the calibration of g spectrometers difficult. The uniform falling velocities of the 133Ba disk source and 137Cs point source were used to calibrate the detection efficiency of 133Xe volume source and 137Cs linear source. The non-uniform falling velocities of 133Ba disk source and 137Cs point source were used to calibrate the detection efficiency of heterogeneous 133Xe volume source and heterogeneous 137Cs linear source. The results show that the detection efficiencies of 133Xe were 0.155 (for f46.8 mm20 mm sample) and 0.143 (for f63.5 mm20 mm sample) respectively, obtained for the uniform falling velocity of the source, and the uncertainty was 8.4% (k=2). The deviation between the efficiency of the heterogeneously distributed volume source and the efficiency of uniform volume source in 14%, and 23% for linear sources. Therefore, the deviation caused by heterogeneity must be corrected.