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1

Algorithms for digital γ-ray spectroscopy

Guzik Z., Krakowski T.

Nukleonika

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2013

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Vol. 58, No. 2

333--338

EN

The data processing in modern nuclear spectroscopy is dominated by digital methods. In this paper we present a full set of algorithms necessary for energy reconstruction, baseline restoration, trigger generation and selection of events (acceptation) which are based on digital signal processing (DSP) techniques. All algorithms were fully evaluated using mathematical apparatus of Z-transform. The energy reconstruction algorithm is based on trapezoidal shaping. The baseline restoration makes the use of a digital moving average, while trigger generation algorithm utilize a digital form of RC-CR2 filter with protection windowing. The evaluated algorithms has been implemented and used in the demonstrator build for national borders protection.

2

Natural radioactivity in building materials in Iran

Mehdizadeh S., Faghihi R., Sina S.

Nukleonika

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2011

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Vol. 56, No. 4

363-368

EN

This work presents a comprehensive study of natural radioactivity in building materials used in Iran. For this purpose, 177 samples of five types of building material, i.e. cement, gypsum, cement blocks, gravel and brick, were gathered from different regions of the country and analyzed by gamma spectroscopy to quantify radioactivity concentrations using a high purity germanium (HPGe) detector and a spectroscopy system. According to the results of this investigation, cement samples had maximum values of the mean Ra-226 and Th-232 concentrations, 39.6 and 28.9 Bq/kg, respectively, while the lowest value for mean concentration of these two radionuclides were found in gypsum samples 8.1 and 2.2 Bq/kg, respectively. The highest (851.4 Bq/kg) and lowest (116.2 Bq/kg) value of K-40 mean concentration were found in brick and gypsum samples, respectively. The absorbed dose rate and the annual effective dose were also calculated from the radioactivity content of the radionuclides. The results show that the maximum values of dose rate and annual effective dose equivalent were 53.72 nGy/h and 0.37 mSv/y in brick samples. The radium equivalent activities Req calculated were below the permissible level of 370 Bq/kg for all building materials. The values of hazard indexes were below the recommended levels, therefore, it is concluded that the buildings constructed from such materials are safe for the inhabitants. The results of this study are consistent with the results of other investigations in different parts of the world.

3

The effects of Holocene podzolisation on radionuclide distributions and dose rates in sandy coastal sediments

Nielsen A. H., Murray A. S.

Geochronometria

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2008

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Vol. 31

53-63

EN

This study analyses the effect of a specific kind of soil development, podzolisation, on selected radionuclide concentrations and the derived dose rates. 100 samples from four sandy, podzolised regions in Jutland, Denmark, were dated by luminescence dating. Dose rates were determined by gamma spectrometry. Of the 100 samples, 31 were retrieved from three profiles intersecting soil horizons affected by podzolisation. At 35 locations, additional material was collected for supplementary geochemical analyses (soil pH, organic carbon content and extractable iron and aluminium). The geochemical data and grain size data were correlated with radionuclide activity concentrations. These correlations do not indicate any significant relationship between organic carbon or extractable iron/aluminium and radionuclide concentrations; this suggests that the radionuclides are mainly internally bound in primary minerals, unlike the extractable iron, which is generally associated with surface coatings. We conclude that the radionuclide distribution in these young sandy soils has been relatively unaffected by the podzolisation process. Thus it appears that the dose rate at these sites is unlikely to have changed significantly with time as a result of podzolisation, because the parent material is relatively unweathered and the activity is dominated by internally bound radionuclides.