Calibration of an HPGe detector and self-attenuation correction for 210Pb: Verification by alpha spectrometry of 210Po in environmental samples

Abstract

In this work the calibration of an HPGe detector for 210 Pb measurement is realised by a liquid standard source and the determination of this radionuclide in solid environmental samples by gamma spectrometry takes into account a correction factor for self-attenuation of its 46.5 keV line. Experimental, theoretical and Monte Carlo investigations are undertaken to evaluate self-attenuation for cylindrical sample geometry. To validate this correction factor, 210 Po (at equilibrium with 210 Pb) alpha spectrometry procedure using microwave acid digestion under pressure is developed and proposed. The different self-attenuation correction methods are in coherence, and corrected 210 Pb activities are in good agreement with the results of 210 Po. Finally, self-attenuation corrections are proposed for environmental solid samples whose density ranges between 0.8 and 1.4 g/cm 3 and whose mass attenuation coefficient is around 0.4 cm 2 /g.

Comparative study of natural radiation exposure to the public in three uranium and oil regions of Cameroon

“…A sodium iodide (NaI) detector was used to measure radioactivity in samples collected in Bakassi. Uncertainty assessment of activity concentrations is well described in Saïdou et al (2007Saïdou et al ( , 2008. More details about the sampling and conditioning, characteristics, energy and efficiency calibration of the above detectors can be found in references (Saïdou et al, 2007(Saïdou et al, , 2008(Saïdou et al, , 2011Ele Abiama et al, 2010).…”

“…Alpha spectrometry using automated borate fusion and sequential extraction and exchange chromatography were used to determine the uranium and thorium isotopes in the samples collected in Poli (Saïdou et al, 2008). Alpha spectrometry using microwave acid digestion under pressure for sample mineralization was used to measure 210 Po in the foodstuffs collected in Poli and Bakassi (Saïdou et al, 2007). Gamma spectrometry was also used to measure radioactivity in the foodstuffs collected in Poli, Lolodorf and Bakassi.…”

Natural radioactivity measurements and dose calculations to the public: Case of the uranium-bearing region of Poli in Cameroon

“…A procedure for measuring U and Th isotopes was developed within the framework of this study and has been fully described previously (Saïdou et al, 2008). The procedure used for measuring 210 Po based on microwave digestion under pressure for polonium solubilisation developed within the framework of this study has also been fully documented in a previous work (Saïdou et al, 2007).…”

“…We then estimated the self-absorption correction experimentally, analytically and using Monte Carlo methods. The procedure is fully described in a previous publication (Saïdou et al, 2007).…”

“…In this context, a procedure for measuring U and Th isotopes using alpha spectrometry has been specially developed for this study and already published elsewhere. Furthermore, knowing the high radiotoxicity of 210 Pb and 210 Po, two methods for measuring 210 Po using alpha spectrometry and 210 Pb using gamma spectrometry were developed and also published elsewhere (Saïdou et al, 2007). Finally, the indoor radon concentration was measured in a few dwellings in order to estimate the overall annual dose received by the public.…”