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  • Author or Editor: M. Misdaq x
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Abstract  

Uranium and thorium contents in different drinking water samples have been evaluated by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD) and calculating the probabilities for -particles to reach and be registered on the SSNTD films. A new method has been developed based on calculating the stopping powers of the studied material for the - and -particles emitted by the nuclei of the uranium and thorium series for evaluating - and -dose rates of the considered water samples. The influence of the soil nature of the aquifer on the alpha- and beta-doses in water samples has been investigated.

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Abstract  

Radon-to-thoron ratios as well as radon and thoron activity concentrations in different underground water samples belonging to different aquifers in the Moroccan Middle Atlas area have been evaluated by LR-115 and CR-39 solid state nuclear track detectors (SSNTD) using a new calibration method. The radon isotope (222Rn) was used as a tracer for studying the water exchange between different aquifers of the area studied. The influence of the lithological and hydrogeological parameters of the aquifers on radon emanation were investigated.

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Abstract  

Radon emanation from surface water and groundwater samples has been studied by using CR-39 and LR-115 solid state nuclear track detectors (SSNTD). A calibration method for determining the thoron and radon concentrations of the water samples studied has been developed. The effect of pollution due to coal fly ashes, cement and granite dusts on the radon emanation from water samples has been investigated. The influence of the radon source on the radon emanation rates from water samples has been studied.

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Abstract  

The thorium to uranium ratio has been determined in different geological samples by using a new theoretical method based on calculating the probability for an emitted -particle to reach and be registered on a solid state nuclear track detector (SSNTD). Thorium as well as uranium contents of the samples studied have been determined by exploiting the track densities, due to the -particles of the thorium and uranium series, registered on the CR-39 and LR-115 SSNTD. Results obtained by this calculational method which does not need any calibration were compared to data obtained by isotope dilution mass spectrometry. The influence of the granulation on the uranium content in sedimentary phosphate samples has also been investigated.

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Abstract  

Uranium (238U) and thorium (232Th) concentrations were evaluated in different cereal, fruit and vegetable samples by using a method based on the calculation of the detection efficiencies of the emitted a-particles by CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD) and measuring the resulting track densities. The influence of the soils on which the plants grow, and the fertilizers used was investigated. Total daily intakes of 238U and 232Th for a typical food basket were estimated to be 1.16 Bq.d-1 and 0.94 Bq.d-1, respectively, corresponding to a total committed effective dose of 0.27.10-7 Sv.d-1. Annual committed effective doses due to 238U and 232Th originated from the ingestion of different foodstuffs were evaluated for the adult members of the population by using the ICRP ingestion dose coefficients.

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Abstract  

Alpha- and beta-activities per unit volume of air due to radon (222Rn), thoron (220Rn) and their progenies were measured in the air of natural caves and ancient mines as well as inside different reference atmospheres by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). In addition, the radon concentration was continuously measured inside one of the studied caves by using the SSNTDs’ method and AlphaGuard counter. Equilibrium factors between radon and its daughters and between thoron and its progeny were evaluated in the studied atmospheres. Alpha-activities due to 218Po and 214Po short-lived radon decay products were determined in different compartments of the respiratory tract of members of the public. The committed equivalent doses due to the 218Po and 214Po radon short-lived progeny were evaluated in different tissues of the respiratory tract of the visitors of the considered caves and ancient mines. Annual effective doses due to radon progeny from the inhalation of air by the visitors of the studied caves and ancient mines were evaluated.

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Abstract  

Radon alpha-activities were evaluated in different places of a quaternary cave, by using solid state nuclear track detectors (SSNTD). The maximum activity was detected in the place more moved back of the studied cave. The ventilation phenomenon has been investigated. The radon alpha activity and uranium content according to the growth of stalagmite and stalactite samples from the cave were evaluated. A positive correlation has been shown between the uranium distribution (radon) and the stratigraphic order of the stalagmite (and stalactite) samples.

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Abstract  

The applicability of 14 MeV neutron activation analysis for the determination of K in beet has been investigated by measuring the 2.167 MeV gamma-line from the decay of38gK produced in the39K(n, 2n) reaction. Beet samples were treated in different solutions of KCl and HgCl2 to study the diffusion of K+ ions into the beet cells. The contribution of the gamma-line to the measured peak area from38Cl produced in the37Cl(n, γ) reaction was found to be 1%. Results obtained by fast neutron activation analysis and by flame spectrometry have been compared, and good agreements were found.

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Abstract  

Domestic radioactivity has been studied by using LR-115 and CR-39 solid state nuclear track detectors (SNTD) and a suitable beta- and gamma-gaseous counter. A new calibration method, based on measuring thoron (220Rn) to radon (222Rn) ratios, has been developed for determining the -activity originating from radon in different Marrakechi dwellings. The influence of building materials as well as pollution and airing factors, on domestic radioactivity has been investigated.

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