Experimental Characterization of a
Lightweight Unmanned Aerial Radiation
Detection System equipped with a “Flat
Panel” gamma detector.

The capability of performing radiological monitoring of large areas using a lightweight, rapidly mountable gamma detection system is demonstrated. The system was designed to deliver radiological information such as count rate, dose rate and gamma energy spectra to first responders in response to a nuclear / radiological incident. The “Flat Panel” gamma detector, developed by Arktis Radiation Detectors, relies on plastic scintillation and Silicon Photomultiplier light readout: this solution maximizes performance in terms of efficiency per unit weight, while being highly insensitive to electromagnetic fields, vibrations, and mechanical shocks. With a single flight autonomy of more than 20 minutes, the capability of scanning large areas in radionuclide-localization missions is demonstrated by means of field tests performed at the Spiez CBRN Laboratory in Switzerland. In each test, gamma-emitting radionuclide sources with activities from hundreds of MBq to few GBq and energies ranging from 60 keV to 1.3 MeV have been deployed in a field of 15’000 m2 and flight patterns at different speed and altitude are carried out in order to assess detection limits. Dose rate heat-maps are generated for different incident gamma energies to validate a dose rate calculation algorithm based on spectroscopic analysis. The measurement results show that the system can reliably localise radionuclide sources in large-area scans in less than 20 minutes, while providing dosimetric and spectroscopic information to first responders to allow real-time assessment of radiological risks.