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  • Author or Editor: J. Csikai x
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Abstract  

Some methods developed in collaboration between the ATOMKI and IEP for bulk hydrogen analysis and for the detection and identification of illicit drugs are presented. Advantages and limitations of neutron techniques (reflection, transmission, elastic and inelastic scatterings, leakage spectra and angular yields of Be(d,n), Pu–Be, D–D, D–T and 252Cf neutrons transmitted from thick samples, effects of hidden materials) are discussed.

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Abstract  

An X-ray spectrometric method independent of the matrix composition has been developed for the determination of S and Cl in the case of overlapping peaks. The principle of the methods is based on the observation that the sum of the peak areas from S and Cl is independent of their concentration ratios, only the different sections of the peak depend on these values. Using this method the sulphur and chlorine contents have been determined for crude oil samples collected from different geographical regions.

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Abstract  

A method has been developed for determining silicon in aluminium by fast neutron activation. It is based on the separation of two gamma lines by a Ge(Li) detector: the 1.73 MeV line from the product of27Al(n, α)24Na and the 1.78 MeV line from the28Si(n, p)28Al reaction. In the case of aluminium-silicon alloys 100 μg silicon can be determined, with an error of 10% in an aluminium sample of 1 g.

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Abstract  

A neutron physical method for the fast, nondestructive determination of the bitumen content in asphalt concrete has been developed. The determination is performed on cylindrical asphalt concrete samples containing desiccated rubble matrix. Using samples of ∼1000 g and measuring times of 20 min, the reproducibility of the bitumen determination is ±0.15 w%, the sensitivity is 3·10−3 g/g.

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Abstract  

14-MeV neutron activation analysis /NAA/ and radiochemical separation technique were used for the determination of Cu in Hungarian minerals. The separation of Cu from other elements is a possibility to avoid the interferences in the 511 keV -line.

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Abstract  

An improved experimental setup based on the thermalization and reflection of neutrons has been used for the determination of total H content and (O+C)/H atomic ratio in oil samples. The count rate response function for this setup gives a relative error of about ±1.5% and a detection limit of 0.09 H w% in the case of different hydrogeneous samples of 300–500 cm3 volumes. Results obtained for motor and household oils as well as for crude oil samples from Nigeria and Hungary are presented.

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Abstract  

The concentrations of O, Na, Cl, V, Mn and Ni in crude oils of different origins were determined, using sampling (SNAA) and on-stream (ONAA) activation analyses. Samples were irradiated with thermal and fast neutrons produced by a 0.3 mg252Cf source and a 14 MeV generator. The H-content and the C/H atomic ratio have been determined by thermal neutron reflection method using an 18 GBq Pu−Be source.

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Summary  

A new method based on the epithermal neutron activation has been developed for bulk hydrogen analysis. The sensitivity of the activation method for typical sample dimensions is higher by a factor of ~100 than the neutron reflection technique. Analytical expressions are given for the description of the measured flux density of thermalized neutrons as a function of hydrogen content of different samples. Advantages and limitations of thermal and epithermal neutrons in bulk hydrogen analysis using the foil activation method are also discussed.

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Abstract  

A gamma-spectrometric method independent of radon escape for the determination of U and Ra in rock samples based on the 63 keV and 1001 keV as well as 185 keV lines is described and discussed. A simple experimental procedure is given for the determination of the self-absorption factor. The method has been applied for the determination of uranium and radium in rock samples from Morocco containing uranium between 17.5 wt.% and 0.026 wt.%. The limits of determination, at 95% confidence level and 10% standard deviation, for the 63 keV and 1001 keV lines were found to be 0.075 wt.% and 0.62 wt.%, respectively, using samples of 6 g and chosing 1 h measuring time.

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Abstract  

Utilization of a sealed tube neutron generator requires the knowledge of the lateral flux density distribution and the mean energy of primary neutrons near to the target. The ion composition of the incident beam is related to the operating conditions of a generator. These parameters have been determined for a KAMAN A-711 sealed tube machine by the foil activation method using different energy and fluence monitor reactions. An analytical expression is also given for the calculation of the relative flux density for a typical geometry.

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