RESUMO
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.
Assuntos
Poluentes Radioativos do Ar/análise , Amerício/análise , Monitoramento de Radiação/métodos , Espectrometria gama/métodos , Contaminação Radioativa do Ar/análise , Aeronaves , Simulação por Computador , França , Humanos , Limite de Detecção , Monitoramento de Radiação/instrumentação , Monitoramento de Radiação/estatística & dados numéricosRESUMO
One of the features of the spectra obtained by airborne gamma spectrometry is the low counting statistics due to a short acquisition time (1 s) and a large source-detector distance (40 m) which leads to large statistical fluctuations. These fluctuations bring large uncertainty in radionuclide identification and determination of their respective activities from the window method recommended by the IAEA, especially for low-level radioactivity. Different types of filter could be used on spectra in order to remove these statistical fluctuations. The present work compares the results obtained with filters in terms of errors over the whole gamma energy range of the filtered spectra with the window method. These results are used to determine which filtering technique is the most suitable in combination with some method for total stripping of the spectrum.
