A method for determining Am-241 activity for large area contamination

Airborne gamma-ray spectrometry system HELINUC™ is used for different missions. Although well-developed for estimation of high energy emitters' activity, it is rarely used for low energy emitters. A new method for the determination of Am-241 activity over extended sites based both on statistical analysis of spectra and deconvolution of Am-241 signal with a reference library is presented. Results show a lowering of the detection threshold and a good agreement with ground level measurements.