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Abstract  

It is the aim of this paper, to demonstrate the manyfold interrelation between radiochemistry and activation analysis. One of the main problems of both fields is the behaviour of submicro concentrations of elements and of their compounds in solids, in solution and in the gas phase. The radiochemists were the first, who have accumulated much experience, investigating the properties of the natural radionuclides. HEVESY has, somewhat later, by his proposal of activation analysis, pointed out a special and powerful way for the determination of submicro amouts of substances. In the further development till to the present day, both fields have stimulated each other. Their exponents are specialists in understanding and handling submicro concentrations, i.e. in a section of science and technology, growing up to an outstanding importance.

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Abstract  

The monostandard method with the use of Ge(Li) γ-spectrometry has been elaborated with a critical evaluation of the nuclear data involved in activation and activity measurement. The method was tested by analysing simultaneously 15 elements in a well known standard material of Kale powder and 12 elements in NBS standard glass samples. The results are compared with the reported data to prove the accuracy of the monostandard method.

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Abstract  

Certain elements which are not possible to detect with conventional neutron activation analysis can be measured using thermal neutron-capture gamma-ray analysis. The use of a curved neutron guide at the High Flux Reactor, Grenoble, with a thermal neutron flux of 1.5·1010n·cm−2·sec−1 and the advantage of a low-background counting system (Ge(Li) detector) far from the reactor core are described. Experimental detection limits of a number of elements are given for the low-energy and the high-energy regions. Some applications of the capture gamma-ray method in the whole energy range are studied and are briefly discussed.

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Abstract  

The importance of the extraction medium and its film geometry to the separation efficiency is illustrated by the example of the chromatographic extraction systems HDEHP-HCl-Eu3+ and TBP-HNO3−Sc3+. Starting from the geometry of the matrix, the effects of the exchange kinetics and flow pattern were experimentally proved. Exchange kinetics are described as a heterogeneous transport-limited reaction in the aqueous phase. Four ranges of the rate of exchange with the geometry of the matrix (pore diameter) were found. The flow patterns in the chromatographic layer can be established by the individual pore cross-sectional area of the matrix. The sum of the effects of exchange kinetics and flow patterns determines the chromatographic efficiency of the systems. Their relative effects in the two systems being investigated are discussed.

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Abstract  

In the course of ion-exchange separations of highly active solutions, the radiolysis gives rise to considerable disturbances and deteriorated separation results. On the example of241Am/242Cm separations some results of radiolysis investigations for Dowex 50X8 are briefly shown, and experiences with the choice of parameters of a high-pressure column system are described for several examples.

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Abstract  

A new approach is presented for neutron activation analysis using the monostandard (single comparator) method. Elements to be determined are classified into two groups; those with σo>Io are activated with whole neutron spectrum (without Cd-cover), using a standard of the same group (e.g. Sc), while elements with Ioo are activated with epithermal neutrons (under Cd-cover) using a standard of the same group (e.g. Au or Co). Epithermal activation increases the number of determinable elements and its coupling with the monostandard method has the advantage of using a small Cd-cover. The σo and I0 values of some elements were determined to test this approach.

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Änderung der Leistungfähigkeit Chromatographischer Systeme beim Übergang zu Hohen Aktivitäten

I. Vergleich der Alpha- und Gammaradiolyse eines Kationenaustauschers Bezüglich Seiner Änderungen des Gewichtes, der Salzspalt-und Restkapazität Sowie Seines Quellvermögens

Journal of Radioanalytical and Nuclear Chemistry
Authors: V. Dornow, S. Specht, W. Weinländer, and H. Born

Abstract  

The effect of the alpha and gamma radiation were studied on the characteristics of the cation exchanger resin AG50WX8.

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Änderung der Leistungsfähigkeit Chromatographischer Systeme beim Übergang zu hohen Aktivitäten

II. Vergleich des Einflusses der α-und γ-Radiolyse Eines Kationenaustauschers Auf Verteilungskoeffizienten, Trennfaktoren und Bodenhöhen

Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Specht, V. Dornow, W. Weinländer, and H. Born

Abstract  

The effect of the alpha and gamma radiation were studied on the characteristics of the cation exchanger resin AG 50WX8.

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