Abstract: This paper introduces in detail the composition of UAV radioactive aerial survey system equipped with LaBr₃ detector. The radiation energy is calibrated and the energy resolution and background are tested with the UAV system. The Monte Carlo method is applied to calculate the detection efficiency and conversion coefficient of measuring point source and soil bulk source. The minimum detectable activity (MDA) of the system for point source and volume source at 1 500 s measurement time is calculated. The result shows that the energy resolution of ¹³⁷Cs 661.7 keV is 2.75%. MDA of ¹³⁷Cs point source and bulk source is 2.4 kBq and 3.8 Bq/kg, respectively, at 1 500 s measurement time. The field application shows that, this system can be flexibly applied to radioactive detection in port freight yard.

Key words: LaBr₃, radioactive detection, remote control, nuclide identification