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.
The empirical coefficient method represents the absorption and enhancement effect of each element on each other by parameters independent of mass concentrations. This method is used together with the internal standard method for the determination of cadmium, bromine and selenium by 14 MeV neutron activation followed by X-ray spectrometry. The results of analysis show a relative error not more than ±5%.
A method is described for the simultaneous determination of cadmium, antimony and praseodymium by 14-MeV neutron activation analysis based on characteristic X-ray spectrometry. The results of analysis show a relative error not higher than ±5%, when diluted with H3BO3 /90%/ and utilizing the internal standard method to minimize the interelement effects.
14 MeV neutron activation followed by X-ray spectrometry was applied to the simultaneous nondestructive determination of cadmium, antimony and bromine, utilizing praseodymium as an internal standard. The results of analysis show a relative error not higher than ±5%, when the samples were diluted with H3BO3
-5% to minimize the interelement effects.
An activation analytical method has been developed for determining Cd, Ag, Sb, Se, Br by 14 MeV neutron-induced X-ray emission spectroscopy using Pr as an internal standard. A good correlation was obtained between the activity ratio, RAo and the weight ratio, RW. Results are given after correction for self-absorption and without correction. The results are comparable in both cases when dilution with H3BO3 (90%) is applied. The elements listed can be determined at minor concentrations (0.01%) with a relative error not more than ±5%.
The problem of converting measured intensities into mass concentrations arises from the fact that the measured intensity of a characteristic X-ray line of an element or compound depends not only on the mass concentration of that element or compound but also on the nature and abundance of the other constituents of the specimen. In this work the empirical coefficient method which comprises both absorption and enhancement effects of each element on each other element by parameters independent of mass concentrations was used for correction of enhancement effects from antimony and praseodymium on bromine in two groups of samples. The results of analysis of bromine shows a relative error of not more than ±4%.
The intensity of characteristic X-rays emitted from one element may be reduced by partial absorption by other elements in the matrix, or alternatively it is enhanced by their presence. In this work the enhancement effect of antimony on bromine, cadmium and selenium are given. The dependence of the specific activity of each element /Cd, Br and Se/ on the ratio of the weight of Sb to that of the element is given, when the concentration of Sb is not very low /-5%/.
14 MeV neutron activation of ternary copper silver selenide gives rise to a predominant activity from the 0.511 MeV annihilation peak from the three elements when -ray spectrometry is used. To overcome the interference problems, X-ray spectrometry was applied to the simultaneous nondestructive determination of silver and selenium, after which copper can be determined by -ray spectrometry. The results of analysis show a relative error not higher than ±5%, when the samples were diluted with H3BO3 /90%/ to minimize the interelement effects.
Authors:A. El Barouni, L. Bakos, and Éva Zemplén-Papp
The possibility of using characteristic X-rays from radioactive elements activated with neutron generator has been investigated with particular emphasis on /n, n/, /n, 2n/, /n, p/ and /n, / reactions. X-rays have been emitted from nuclei by electron capture or internal transition processes. The products of six elements seem to be usable for analytical purposes.
Authors:Z. Papp, Z. Dezső, A. Bolyós, and S. Daróczy
Absorption method is shown to be suitable for direct determination of pure β-emitting, isotopes in samples containing more
than one β-emitter. This method consists of (1) measurement of the β-counting rate as a function of the thickness of the absorber
placed in between the sample and the β-detector and (2) decomposition of the complex absorption curve by computation in order
to obtain the contributions of the nuclides to the total counting rate one by one. The method is presented through two examples
of its practical application in the field of environmental radioanalysis:90Sr and147Pm isotopes were determined in aerosol samples contaminated by Chernobyl radioactivity and in hot particles of Chernobyl origin
using a simple end-window Geiger-Müller counter as a β-detector.