LAUSR

A study of a small airborne gamma spectrometer usability, carried by unmanned aerial vehicle (UAV), during a search for radionuclide sources and estimating their activity was performed. Model calculations of calibration coefficients for Georadis D230A spectrometer (with two NaI (Tl) 2″ x 2″ detectors), 241Am, 57Co, 137Cs, 192Ir, 60Co and 152Eu radionuclides and set of flight altitudes from 1 up to 25 m were done. The results were compared with the results of experimental measurements for 137Cs and 60Co sources using vertical heights up to 10 m above the source on the ground. Simulated and discussed is the possible significant influence of the source construction and housing and the position/orientation of the source (due to non-isotropic emission) to estimate the activity of an unknown source. The influence of the natural background and estimation of flight line spacing requirements when planning a UAV route to ensure source localization depending on its activity are discussed.