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The Full Spectrum Analysis approach was applied to obtain activity concentration estimations for in situ measurements in the marine environment. The ‘standard spectra’ were reproduced using the MCNP-CP code. In order to extract the activity concentrations, χ 2 minimization calculations were performed by implementing the MINUIT code. The method was applied to estimate the activity concentrations for measurements in the marine environment in three different test cases. The estimated activity concentrations were in good agreement with the experimentally derived ones within uncertainties. [ABSTRACT FROM AUTHOR]

Abstract: The in-situ underwater gamma-ray spectrometry method is validated by inter-comparison with laboratory method. Deployments of the spectrometer KATERINA on a submarine spring and laboratory measurements of water samples with HPGe detector were performed. Efficiency calibrations, Monte Carlo simulations and the Minimum Detectable Activity (MDA) estimations were realized. MDAs varied from 0.19 to 10.4 (lab) and 0.05 to 0.35 (in-situ) Bq/L, while activity concentrations differed from 7% (for radon progenies) up to 10% (for 40K), between the two methods. [Copyright &y& Elsevier]

Abstract: A new detection system named “KATERINA” is developed and applied for measuring marine radioactivity using NaI(Tl) as a crystal. This apparatus is designed for qualitative and quantitative radionuclide detection in the marine environment with maximum depth of deployment 400m. A detailed study for the enclosure of the system and for the electronics development is performed. The system offers volumetric activities in Bq/m3 using the marine efficiency calibration, which is measured by dilution of three reference sources (99mTc, 137Cs, and 40K) in a special tank. The calibration procedures for energy, energy resolution and efficiency were analyzed with particular attention to the factors that affect the calibration parameters. The underwater detector is tested in the field for acquiring radon daughters (214Pb and 214Bi) in a region where submarine groundwater discharge exists in the coastal zone. [Copyright &y& Elsevier]

Abstract: Sediment samples have been collected in the Butrint area, located in the south-west Albania to determine the radioactivity levels of 40K, 137Cs, 212Bi, 212Pb, 214Bi, 214Pb, 226Ra and 228Ac on the bed of the lagoon and adjacent sea, using direct counting gamma spectroscopy. The concentration of 137Cs and 40K varied from 2.8 to 37.5Bq/kg and from 266 to 675Bq/kg dry weight (dw), respectively (central values). The average concentrations of 238U and 232Th daughter products varied from 8 to 27Bq/kg and from 13 to 40Bq/kgdw, respectively. The measured 235U activity ranged from 0.7 to 2.5Bq/kgdw. Samples of different sedimentary properties, studied for the radioactivity concentration, revealed an inversely proportional relation between grain size and a linear combination of measured specific activities of 226Ra, 232Th (228Ac, 212Bi and 212Pb), 40K and 137Cs. [Copyright &y& Elsevier]