Well GeHP detector calibration for environmental measurements using reference materials

International audienceA well-type detector installed in the Modane underground Laboratory (LSM) can combine both low background and high detection efficiency and it is well suited for the analysis of small amounts of environmental samples. Reference materials such as IAEA-447 (moss-soil), IAEA-RG-Th1 and IAEA-RG-U1 were used for the detector calibration, owing to a chemical composition close to those of the environmental samples. Nevertheless , the matrix effects and the true coincidence summing effects must be corrected from the full energy peak efficiency (FEPE). The FEPE was performed for a wide range of energy by a semi-empirical method using Monte Carlo simulation (MCNP6), intended for environmental measurements such as lake sediments dating. In the well geometry, the true coincidence summing effects could be very important and correction factors have been computed in three different ways

Evaluation of radionuclide concentrations and external gamma radiation levels in phosphate ores and fertilizers commonly used in Algeria

International audienc

Annual effective dose and excess life time cancer risk assessment from tobacco plants

International audienceCigarette smoking is one of the pathways that might cause radiation exposure due to the presence of radioactive elements in tobacco leaves used in the manufacture of cigarettes. From the health point of view, the knowledge of radioactivity content of the various radionuclides in tobacco leaves and their derivative products is important to assess the radiological effects associated with tobacco smoking for smokers. In this work, naturally occurring radionuclides 226 Ra, 232 Th and 40 K and man-made 137 Cs were measured in tobacco using gamma-ray spectrometry. Results show that the average concentrations of 226 Ra, 232 Th and 40 K vary from 4.30 ± 0.2 to 11.85 ± 0.7 (average 8.17), 1.35 ± 0.1 to 16.12 ± 0.9 (average 6.08), and 565.6 ± 15.5 to 1235.81 ± 35 (average 908.09) Bq kg −1 , respectively. 137 Cs activity concentrations were ranged from 0.15 ± 0.01 to 0.67 ± 0.9 (average 0.44) Bq kg −1. The most important radiological parameters, including radium equivalent (Ra eq), total annual effective dose (AED) and excess lifetime cancer risk (ELCR) were calculated. For smokers, the total AED resulting from activity concentrations of 226 Ra, 232 Th and 40 K in tobacco samples ranged from 0.44 to 2.29 (average 1.39) mSv y −1 , while of 137 Cs varied from 0.01 to 0.04 (average 0.025) Sv y −1 and so very little is contributing to the total dose due to inhalation to smokers. ELCR was higher than the world's average of 1.45 × 10 −3 for tobacco and coal samples. The excess lifetime cancer risk ranged from 1.55 × 10 −3 to 8.01 × 10 −3 with an average value of 4.88 × 10 −3 for all tobacco samples under investigation