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 γspectrometers 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 ■46.8 mm×20 mm sample) and 0.143 (for ■63.5 mm×20 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.