RESUMEN
The sum-peak method principally enables determination of the absolute activity of gamma cascade emitting sources based only on the use of spectral data, without knowledge of the detector efficiencies. However, to achieve better accuracy of the activity results, corrections due to pile-up, accidental coincidences, electronic noise and angular correlations must be introduced into the proposed method. Such corrections usually require the collection of a few gamma spectra and additional extrapolations, thereby further complicating the experimental procedures. In this paper, it is shown that by using pile-up peaks for corrections of accidental coincidences, Monte Carlo techniques for angular correlation, and LLD corrections, the source activity can be measured with accuracy and reproducibility below 1% using only one gamma spectrum, without any additional extrapolations.
RESUMEN
The radon emanation and the granulation effect on the emanation rate of several building materials (ceramic plates, sand, red brick and siporex brick) with different (226)Ra concentrations were investigated. A ball mill was used to achieve different granulations of the materials. The particle size distributions were determined by a particle size analyser (Mastersizer 2000). The increase in the (222)Rn concentration inside a closed chamber (volume ≈5.4 × 10(-3) m(3)) due to emanation from each material with different granulations was measured by an alpha spectrometer (RAD7). Thus, time-dependent curves for radon concentrations were obtained. The highest radon emanation coefficient (27 %) was obtained for the siporex sample with the smallest grain size (0.34 µm). For the ceramic pads, the granulation effect was negligible and the emanation coefficient was very low (â¼0.4 %). The strongest influence of granulation on the radon emanation rate was found for the siporex brick sample.
Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Materiales de Construcción/análisis , Radón/análisis , Dióxido de Silicio/química , Vivienda , Humanos , Tamaño de la PartículaRESUMEN
Antiphospholipid syndrome (APS) is an autoimmune disease which is characterized by arterial and venous thromboses, fetal loss, and the presence of antiphospholipid antibodies in the serum (aPL). It is characterized by accelerated atherosclerosis and that together with an increased tendency towards thrombosis leading to the occurrence of various vascular events. Timely diagnosis of vascular changes, preferably in subclinical phase, is required due both to their severity and to the high mortality rate. Detection of arterial and venous changes nowadays is performed through diversity of invasive and non invasive diagnostic methods. 64-multi slice computed tomographic angiography (64-MSCT) seems to be the most precise method with low exposure time, giving the opportunity for clinicians to early diagnose and timely treat APS patients.
Asunto(s)
Síndrome Antifosfolípido/complicaciones , Síndrome Antifosfolípido/diagnóstico , Enfermedades Vasculares/diagnóstico , Enfermedades Vasculares/etiología , HumanosRESUMEN
The results of indoor radon survey in the South-Pannonian Province Vojvodina (Serbia and Montenegro) are presented. The sampling strategy was oriented towards suburban and urban regions in the Province. For the dwellings typical for such regions the geometric mean annual radon activity concentration of 76.1 Bq m(-3) is measured (1000 measurements). This result leads to the annual dose estimate of 4.3 mSv y(-1), which is above the recommended action limit of ICRP. For urban dwellings in Novi Sad (the Province capital), the annual mean value of 54 Bq m(-3) (220 measurements) is obtained. By comparison of these two results it is concluded that radon surveys based on measurements in urban environment may seriously underestimate the radon-related health risk. The elevated radon levels could not be explained by elevated uranium levels of surface soil.
Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Contaminación del Aire Interior/análisis , Contaminación del Aire Interior/estadística & datos numéricos , Monitoreo de Radiación/métodos , Radón/análisis , Población Rural/estadística & datos numéricos , Dosis de Radiación , Medición de Riesgo/métodos , Factores de Riesgo , YugoslaviaRESUMEN
The Bega canal is one among many heavily polluted canals in Vojvodina (the northern province of Serbia and Montenegro). In the framework of the revitalization of this canal, the radionuclide content of the sediment was investigated in order to support the safe deposition after excavation. It was found that, in comparison with the Danube sediment and Vojvodina soil, the Bega sediment is contaminated with (238)U and (137)Cs. The origin of this contamination is discussed. No traces of contamination by nuclear power plants in the region were found, while the presence of technologically enhanced, natural occurring radioactive materials (TENORM) was proved.