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  • Author or Editor: T. Bereznai x
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Abstract  

The shape of the epithermal neutron energy distribution has been determined in two irradiation positions of the University of London CONSORT II reactor. The method applied involves cadmium ratio measurements using a series of resonance detectors. Principles of the method and some considerations relative to epithermal neutron activation analysis in connection with the deviation of the epithermal neutron flux distribution from the 1/E law are given.

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Résumé  

On rapporte les recherches faites sur les couches épitaxiques déposées sur des substrats dopés en arsenic, antimoine et phosphore. On étudie les couches critiques par analyse par activation et autoradiographie. On détermine les répartitions des concentrations des éléments dopants et des traces d'impuretés les plus fréquentes, telles que l'or, le cuivre et le sodium, dans la couche superficielle et dans l'interface film-substrat des couches homoépitaxiques de silicium. Dans les conditions expérimentales données, on trouve que la concentration contaminante minimum décelable est d'environ 1013 atomes/cm3.

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Abstract  

The possible extension of the comparator technique of reactor neutron activation analysis into the field of epithermal neutron activation has been investigated. Ruthenium was used for multi-isotopic comparator. Experiments show that conversion of the so-called reference k-factors—determined by irradiation with reactor neutrons—into kepi-factors usable at activation under cadmium filter, can be evaluated with fair accuracy. Sources and extent of errors and their contribution to the final error of analysis are discussed.

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Abstract  

In our determination of trace element contents of animal tissue by neutron activation analysis in the course of structure-activity relationship studies on platinum containing cancer drugs and wound healing we have tried to minimize the blank values that are caused by different sources of contarnination during surgery, sampling and the activation analysis procedure. The following topics have been investigated: the abrasions from scalpels made of stainless steel, titanium or quartz; the type of surgery; the homogenisation of the samples before irradiation by use of a ball mill; the surface contaminations of the quartz ampoules that pass into the digestion solution of the irradiated samples. The appropriate measures to be taken in order to reduce the blank values are described. The results of analyses performed under these conditions indicate the effectiveness of the given measures, especially shown by the low values obtained for the chromium contents of the analysed muscle samples.

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