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  • Author or Editor: P. Bussiere x
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Abstract  

An apparatus is described that enabled us to carry out a quantitative kinetic investigation of rather quick physicochemical transformations of divided solids by means of an emission of radioactive gas, as in the emanation method. Especially the details of the reaction cells are given in which surface area measurements by the BET method are also performed, and of the low volume scintillation chamber. Its high efficiency does not depend on the nature of the gas. The diverse components of the device ensure a good quality of pure atmosphere or vacuum, rapid and precise temperature setting and control, and reproducible sweeping of the radioactive gas escaping from the sample.

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Résumé  

Les auteurs présentant leur expérience des dosages de routine non destructifs, dans le domaine cité en titre, réalisés à la précision relative de 1 à quelques pour cent pour des quantités minimales d'éléments divers comprises entre 0,05 et 20 μg. Ils discutent les principales sources d'erreur, surtout les gradients de flux de neutrons dûs soit au réacteur soit à l'autoabsorption.

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Abstract  

A method applicable for serial determination of traces of chlorine in SiO2−Al2O3 catalysts by neutron activation is described. The results are evaluated by means of a computer. The38Cl activity is subtracted from the activity of the interfering components (56Mn,24Na) and this enables a direct γ-spectrometric determination. In praxis ten samples should be irradiated simultaneously and for this reason 3 standards are irradiated together with the samples to correct for the fluxus gradient. The reproducibility of the method is better than 2 per cent for 10–300 mg samples with a Cl content of 10 ppm.

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