An Operational Data Management Approach for Helicopter-based Aerial Radiation Measurements in Emergency Preparedness...

Helicopter-based aerial radiation surveys are essential tools for rapid wide-area dose rate assessment during nuclear emergency preparedness and response; however, their reliability depends strongly on effective data management, background correction, and quality control under complex operational conditions. This study proposes and validates an operational data management approach for helicopter-based aerial radiation measurements using large-volume NaI(Tl) detectors. Field experiments conducted at different flight altitudes were used to evaluate background radiation components, attenuation effects, and data consistency. Altitude-profile maritime flights and linear regression analysis enabled separation of helicopter-related and altitude-dependent background contributions, while Monte Carlo simulations, assuming an infinite half-space ground distribution, were used to derive altitude-dependent attenuation correction factors for converting aerial measurements to dose rates at 1 m above ground level. The reliability of the corrected aerial survey results was verified through statistical comparison with carborne survey data, demonstrating overall consistency despite differences in measurement geometry and spatial averaging. In addition, the BG-index and Cs-index methods were shown to provide a robust means of discriminating between background radiation and radioactive cesium under low count rate and high-altitude conditions. The results confirm that the proposed approach provides a practical and reliable framework for wide-area dose rate mapping in nuclear emergency preparedness and response.