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  • Author or Editor: G. Török x
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Abstract  

The present state of a long term program is reviewed. It was started to elaborate a remote controlled automated radiochemical processing system for the neutron activation analysis of biological materials. The system is based on wet ashing of the sample, followed by reactive desorption of some volatile components. The distillation residue is passed through a series of columns filled with selective ion screening materials to remove the matrix activity. The solution is thus “stripped” from the interfering radioions, and it is processed to single-elements through group separations using ion-exchange chromatographic techniques. Some special problems concerning this system are treated. (a) General aspects of the construction of a (semi)automated radiochemical processing system are discussed; (b) Comparison is made between various technical realizations of the same basic concept; (c) Some problems concerning the “reconstruction” of an already published processing system are outlined.

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Abstract  

Based on the method of SAMSAHL a programmed, semi-automated processing system has been developed and tested for the neutron activation analysis of the following elements: As, Se, Sb, Br, Sn and Te. The main characteristics of the procedure are the following: wet ashing of the sample (by means of digestion in a mixture of concentrated sulphuric acid and hydrogen peroxide), bromination, and chlorination. The procedure is controlled via the appropriate dosage of the reagents and a carefully managed thermal balance. The chemical yield and its reproducibility were determined by tracer techniques using exactly the same parameters as for the active runs. According to the results the method can be used for the routine determination of the given elements except antimony.

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Abstract  

Several sorbents were prepared by precipitating zirconium phosphate on activated carbon support material. The main parameters of the chemical procedure were optimized in order to obtain the highest decontamination factors which can be achieved in the case of Cs+, Sr2+ and I ions. For the characterization of the sorbents, sorption isotherms and capacity data were determined. The reproducibility of the preparation is about 10%.

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Abstract  

A control system for monitoring the radioactive concentration in aqueous wastes of nuclear installations was elaborated. The mobile station developed for in situ control enables simultaneous measurement of gamma radiation in the energy range of 0.15–2.0 MeV and that of beta radiation in the energy range of 0.3–2.0 MeV by means of a combined scintillation detector. Disturbing effects of accompanying and secundary radiations on the determination of the counting efficiency vs. radiation energy functions used in calculation of the radioactive concentration limits as well as some experiences during a long time of operation of the system have been discussed.

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Abstract  

For the selective removal of the matrix activity (24Na,32P and42K) in the neutron activation analysis of biomedical samples the inorganic separators “hydrated antimony pentoxide”, zirconium phosphate, and titanium phosphate were prepared. The sorption parameters of the samples were determined via elution chromatography techniques, with appropriate tracers. The basic principles of the sorption processes were investigated, and the experimental conditions were optimized. These inorganic separators were then applied, combined with a distillation procedure and an ion-exchange separation, for the determination of the following trace elements in animal blood samples: Mn, Co, Cu, Fe and Zn.

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