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 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

Il Radgyro: un autogiro dedicato ad acquisizioni airborne multiparametriche

This study summarizes the main characteristic of the Radgyro, an auotgyro dedicated to multiparametric airborne acquisitions. This aircraft was imagined, designed and realized to host two cameras, an infrared camera, a thermographic camera, five gamma-ray spectrometers as well as a GPS antenna network, a inertial navigation system, a radar altimeter and the electronic system necessary to the automatic, simultaneous and independent use of the entire instrumentation. Thanks to a carrying capacity of 130 kg, 4 hours of flight autonomy and a low overhead, the Radgyro is the ideal vehicle for multiparametric surveys of wide areas, where the use of drones is limited by the carrying capacity and by the flight autonomy. Finally the results of preliminary photogrammetric surveys and the possible future applications of the aircraft are presented

The worldwide NORM production and a fully automated gamma-ray spectrometer for their characterization

Materials containing radionuclides of natural origin, which is modified by human made processes and being subject to regulation because of their radioactivity are known as NORM. We present a brief review of the main categories of non-nuclear industries together with the levels of activity concentration in feed raw materials, products and waste, including mechanisms of radioisotope enrichments. The global management of NORM shows a high level of complexity, mainly due to different degrees of radioactivity enhancement and the huge amount of worldwide waste production. The future tendency of guidelines concerning environmental protection will require both a systematic monitoring based on the ever-increasing sampling and high performance of gamma ray spectroscopy. On the ground of these requirements a new low background fully automated high-resolution gamma-ray spectrometer MCA_Rad has been developed. The design of Pb and Cu shielding allowed to reach a background reduction of two order of magnitude with respect to laboratory radioactivity. A severe lowering of manpower cost is obtained through a fully automation system, which enables up to 24 samples to be measured without any human attendance. Two coupled HPGe detectors increase the detection efficiency, performing accurate measurements on sample volume (180 cc) with a reduction of sample transport cost of material. Details of the instrument calibration method are presented. MCA_Rad system can measure in less than one hour a typical NORM sample enriched in U and Th with some hundreds of Bq/kg, with an overall uncertainty less than 5%. Quality control of this method has been tested. Measurements of certified reference materials RGK-1, RGU-2 and RGTh-1 containing concentrations of K, U and Th comparable to NORM have been performed, resulting an overall relative discrepancy of 5% among central values within the reported uncertainty.Comment: 21 pages, 4 figures, 6 table

A preliminary study of gross alpha/beta activity concentrations in drinking waters from Albania

A pilot study involving screening measurements of gross alpha/beta activity concentration in drinking water was performed in 12 cities with the highest population density in Albania. The aim of this study was to develop a first insight regarding the radiological quality of drinking and bottled water supplies. The tap and bottled water samples investigated are acceptable for consumption, complying with the WHO recommendations for drinking water. The average gross alpha and beta activity concentrations were 36þ37 18 and 269þ337 150 mBq/L, respectively in tap waters. While for bottled water the gross alpha and beta activities were respectively 39þ55 23 and 220þ336 132 mBq/L. The data obtained can provide information for authorities regarding the quality of drinking water and a baseline for future contaminations

Uranium distribution in the Variscan Basement of Northeastern Sardinia

We present a detailed map of uranium distribution and its uncertainties in the Variscan Basement of Northeastern Sardinia (VBNS) at a scale of 1:100,000. An area of 2100 km2 was investigated by means of 535 data points obtained from laboratory and in situ gamma-ray spectrometry measurements. These data volume corresponds to the highest sampling density of the European Variscides, aimed at studying the genetic processes of the upper crust potentially triggered by an enrichment of radiogenic heat-producing elements. For the first time, the Kriging with Variance of Measurement Error method was used to assign weights to the input data which are based on the degree of confidence associated with the measurements obtained using different gamma-ray spectrometry techniques. A detailed tuning of the model parameters for the adopted Experimental Semi-Variogram led to the identification of a maximum distance of spatial variability coherent to the observed tendency of the experimental data. We demonstrate that the obtained uranium distribution in the VBNS, characterized by several calc-alkaline plutons emplaced within migmatitic massifs and amphibolite-facies metamorphic rocks, is an excellent benchmark for the study of ‘hot’ collisional chains. The uranium map of VBNS, and in particular the Arzachena minor pluton, confirms the emplacement model based on the recognition of the different petrological associations characterizing the Variscan magmatic processes in the Late Paleozoic. Furthermore, the presented model of the uranium content of the geological bedrock is a potential baseline for future mapping of radon-prone areas

Mapping of Natural Radioelements Using γ-Ray Spectrometry: Veneto Region Case of Study.

The main source of terrestrial gamma-ray radiation exposure to humans comes from 238U, 232Th decay chains and 40K decay. γ-ray spectrometry is a consolidated methodology extensively utilized by many nations for investigating and mapping of natural radioelements. The territory were investigated through γ-ray spectrometry implying measurements utilizing laboratory, portable and airborne instruments in order to realize the thematic maps of radioactivity content and in particular of the abundances of eU , eTh: these concentrations by weight are determined indirectly from 238U and 232Th daughter products (214Bi and 208Tl respectively), that are assumed to be in equilibrium with their parent isotope) and 40K. The Veneto region has 18000 km2 with around 50 different lithological formations and 40% of its territory is covered by mountains and hills while the remaining 60% has a plain geomorphology. Therefore, the survey program was planed taking into consideration the geological, geographical and morphological variability of the territory under investigation and divided in three approaching scales undertaking laboratory, in-situ and airborne measurements following the IAEA guidelines. The Legnaro National Laboratory (LNL) is the national leader for the design and realization of high-resolution γ-ray spectrometers, portable and massive NaI(Tl) detectors. The MCA-Rad γ-ray spectrometry system was designed and built up at LNL for measuring large amount of samples with a minimum wait: 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%

First characterisation of natural radioactivity in building materials manufactured in Albania.

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

Mapping the natural radioactivity of Elba Island by means of geostatistical interpolation of airborne gamma-ray data.

We present the maps of K, eU, and eTh radioelement abundances of Elba Island (Italy) realized by means of a geostatistical interpolation of airborne "-ray data, performed with a module of four NaI(Tl) crystals of 16 L mounted on an autogyro. We applied the Collocated Cokriging (CCoK) multivariate estimator in a non-conventional way for interpolating the under-sampled airborne gamma-ray data using the geologic map as constraining ancillary variable. An arbitrary number has been assigned to each geological formation and used in the algorithm for estimating the radioelement abundances: the independence from the random assignment process has been tested for three distinct models. The spatial variability shows well-defined structures for the linear coregionalization models. The abundance maps indicate a distinct correlation between the geological formation and radioactivity content. High K, eU and eTh abundances were estimated in the intrusive granitic complex of Mt. Capanne and low abundances in the geological formations in the N-E sector of Elba Island. However, a clear anomaly of high K content in the Mt. Calamita promontory confirms the presence of felsic dykes and hydrothermal veins not reported in geological map of Tuscany Region at scale 1:10000. This result confirms that the internal variability of the radiometric data is not biased by the multivariate interpolation