Natural radioactivity in Sardinian granite dimension stones

http://www.fe.infn.it/u/mantovani/CV/Proceedings/Puccini_10b.pd

Exploring the Earth’s mantle with geoneutrinos

The KamLAND and Borexino experiments have observed, each at ∼ 4σ level, signals of electron antineutrinos produced in the decay chains of thorium and uranium in the Earth’s crust and mantle (Th and U geoneutrinos). Various pieces of geochemical and geophysical information allow an estimation of the crustal geoneutrino flux components with relatively small uncertainties. The mantle component may then be inferred by subtracting the estimated crustal flux from the measured total flux. On the base of this approach we find that crustsubtracted signals show hints of a residual mantle component, emerging at ∼ 2.4σ level by combining the KamLAND and Borexino data. The inferred mantle flux slightly favors scenarios with relatively high Th and U abundances, within ±1σ uncertainties comparable to the spread of predictions from recent mantle models

Employment of portable gamma-ray spectrometer in survey and mapping of intrusive complexes: a case study from the Buddusò pluton (Sardinia)

http://www.fe.infn.it/u/mantovani/CV/Proceedings/Puccini_10a.pd

Natural Radioactivity and the Evaluation of Related Radiological Risks in Concrete Used in Prizren District, Kosovo

This study aims to investigate the natural radioactivity levels in concrete made of Portland cement and used in Prizren district, Republic of Kosovo. The activity concentrations of 40K, 226Ra and 232Th were determined by gamma-ray spectroscopy technique with High Purity Germanium (HPGe) detector. The activity concentrations of 40K, 226Ra, and 232Th were found to be 15.4-28.4 Bq kg-1, 4.3-5.9 Bq kg-1 and 2.0-4.1 Bq kg-1, respectively. These results were used to calculate the activity concentration index as recommended by the Basic Safety Standard of Council Directive 2013/59/EURATOM for the safe use of building material. Kosovo must comply with this recommendation in the framework of legislative harmonization with the European Union. The activity concentration index was found to be lower than the reference level of unity (I=0.05), corresponding to an annual effective dose rate of AED=0.05 mSv y-1. The concentration of radionuclides and radiological hazard parameters for concrete investigated in this study were compared with respective results found in literature from different countries. These results show very low activity concentrations, indicating that concrete used in Prizren, Kosovo, does not pose any significant risk due to its use as building material

First characterisation of natural radioactivity in building materials manufactured in Albania

This study focuses on the radiological characterisation of building materials manufactured in Albania by using a high-resolution gamma-ray spectrometer. The average activity concentrations of (40)K, (226)Ra and (232)Th were, respectively, 644.1±64.2, 33.4 ± 6.4 and 42.2 ± 7.6 Bq kg(-1) in the clay brick samples and 179.7 ± 48.9, 55.0 ± 5.8 and 17.0 ± 3.3 Bq kg(-1) in the cement samples. The calculated activity concentration index (ACI), varied from 0.48±0.02 to 0.63±0.04 in the clay brick samples and from 0.29±0.03 to 0.37±0.02 in the cement samples. Based on the ACI, all of the clay brick and cement samples were categorised as A1 materials. The authors can exclude (at 3σ level) any restriction of their use as bulk materials

A new FSA approach for in situ γ\gamma-ray spectroscopy

An increasing demand of environmental radioactivity monitoring comes both from the scientific community and from the society. This requires accurate, reliable and fast response preferably from portable radiation detectors. Thanks to recent improvements in the technology, $\gamma$-spectroscopy with sodium iodide scintillators has been proved to be an excellent tool for in-situ measurements for the identification and quantitative determination of $\gamma$-ray emitting radioisotopes, reducing time and costs. Both for geological and civil purposes not only $^{40}$K, $^{238}$U, and $^{232}$Th have to be measured, but there is also a growing interest to determine the abundances of anthropic elements, like $^{137}$Cs and $^{131}$I, which are used to monitor the effect of nuclear accidents or other human activities. The Full Spectrum Analysis (FSA) approach has been chosen to analyze the $\gamma$-spectra. The Non Negative Least Square (NNLS) and the energy calibration adjustment have been implemented in this method for the first time in order to correct the intrinsic problem related with the $\chi ^2$ minimization which could lead to artifacts and non physical results in the analysis. A new calibration procedure has been developed for the FSA method by using in situ $\gamma$-spectra instead of calibration pad spectra. Finally, the new method has been validated by acquiring $\gamma$-spectra with a 10.16 cm x 10.16 cm sodium iodide detector in 80 different sites in the Ombrone basin, in Tuscany. The results from the FSA method have been compared with the laboratory measurements by using HPGe detectors on soil samples collected in the different sites, showing a satisfactory agreement between them. In particular, the $^{137}$Cs isotopes has been implemented in the analysis since it has been found not negligible during the in-situ measurements.Comment: accepted by Science of Total Environment: 8 pages, 10 figures, 3 table

A multivariate spatial interpolation of airborne {\gamma}-ray data using the geological constraints

In this paper we present maps of K, eU, and eTh abundances of Elba Island (Italy) obtained with a multivariate spatial interpolation of airborne {\gamma}-ray data using the constraints of the geologic map. The radiometric measurements were performed by a module of four NaI(Tl) crystals of 16 L mounted on an autogyro. We applied the collocated cokriging (CCoK) as a multivariate estimation method for interpolating the primary under-sampled airborne {\gamma}-ray data considering the well-sampled geological information as ancillary variables. A random number has been assigned to each of 73 geological formations identified in the geological map at scale 1:10,000. The non-dependency of the estimated results from the random numbering process has been tested for three distinct models. The experimental cross-semivariograms constructed for radioelement-geology couples show well-defined co-variability structures for both direct and crossed variograms. The high statistical correlations among K, eU, and eTh measurements are confirmed also by the same maximum distance of spatial autocorrelation. Combining the smoothing effects of probabilistic interpolator and the abrupt discontinuities of the geological map, the results show a distinct correlation between the geological formation and radioactivity content. The contour of Mt. Capanne pluton can be distinguished by high K, eU and eTh abundances, while different degrees of radioactivity content identify the tectonic units. A clear anomaly of high K content in the Mt. Calamita promontory confirms the presence of felsic dykes and hydrothermal veins not reported in our geological map. Although we assign a unique number to each geological formation, the method shows that the internal variability of the radiometric data is not biased by the multivariate interpolation.Comment: 43 pages, 9 figures, 5 tables. In Remote Sensing of Environment (2013

Preliminary results for the characterization of the radiological levels of rocks in Tuscany Region

http://www.fe.infn.it/u/mantovani/CV/Proceedings/Bezzon_10a.pd

Preliminary results for the characterization of the radiological levels of rocks in Tuscany Region.

The environmental background levels of natural radiation due to the nuclides in rocks vary in significant amounts that depend on the geological and geomorphological features of a territory. The main source of terrestrial gamma-ray radiation exposure to humans is from 238U, 232Th decay chains and 40K decay. This paper reports a part of the results of the Research Project “Measurement of natural radioactivity and mapping of the radioisotope abundances of Tuscany Region”, which started at August 2008 and it is supported by founds of Tuscany Region. The aim of this project is to realize the thematic maps of radioactivity content and in particular of the abundances of eU1, eTh1 and 40K. These goals will be achieved by integrating the information from measurements on samples in laboratory with in-situ investigations and airborne surveys. The Legnaro National Laboratory (LNL) is the national leader for the design and realization of high-resolution gamma-ray spectrometers, portable and massive NaI(Tl) detectors. The MCA_Rad gamma-ray spectrometry system was designed and built up at LNL for measuring large amount of samples with a minimum attendance: these features fit perfectly with the requirements of this project. This system is able to measure any type of materials (solid, liquid, gas), and due to the high efficiency and its geometric symmetry, absolute activity measurements are possible with systematic errors below 5%. http://www.fe.infn.it/u/mantovani/CV/Proceedings/Bezzon_10b.pd

Mapping of natural radioelements using gamma-ray spectrometry: Tuscany Region case of study.

http://www.fe.infn.it/u/mantovani/CV/Proceedings/Bezzon_11a.pd