Application of unmanned aerial vehicles in emergency radiation monitoring

Abstract

The paper is based on experiments within a project to prepare tutorial tasks on a training centre for testing radiation detectors fixed on unmanned aerial vehicles (UAVs) and in unmanned ground vehicles. The paper reports on a small UAV with NaI(Tl) 2“ x 2” detector for radiation monitoring in an emergency event and for radioactive source chasing and detection. The paper is focused on some special cases with the possibility to determine local air kerma rates and the activities of point sources. The detector was calibrated for air kerma rates from 5 nGy h−1 to 20 μGy h−1. The verified model of the NaI(Tl) 2″ x 2″ detector including the electronic module assembled on a UAV was designed in a Monte Carlo simulation. The model was used for calculating the air kerma rates at various altitudes above the ground both for a natural background and for selected point sources. The response functions for 137Cs, 131I, 192Ir, 60Co and 99Mo point sources were calculated by the Monte Carlo simulation to estimate their activities. Experiments were carried out with an NaI(Tl) 2“ x 2” detector fixed on a Robodrone UAV and flying over 60Co and 137Cs point sources over the airfield area and the local air kerma rates and the activities of the point sources were calculated with the AGAMA post-processing program. In addition, the response functions for 137Cs distributed uniformly on the surface were calculated by Monte Carlo simulation for future emergency purposes. The detection limits of selected man-made nuclides (point sources) were calculated.