The background characteristics of large volume HPGe detectors installed in IAEA-MEL's underground counting laboratory situated at a depth of 35 m water equivalent have been investigated. Both single gamma-ray spectra as well as gamma-ray spectra gated by anti-cosmic shielding made of plastic scintillators are presented. The advantages of anti-cosmic shielding for HPGe detectors, especially in underground counting laboratories operating at shallow depths, are discussed. The authors present several examples of analysis of radionuclides in marine samples by single gamma-ray spectrometers with anti-cosmic shielding, an anti-Compton spectrometer and a Ge–Ge telescope designed for the analysis of low energy gamma-emitters.
The authors show that by taking very special precautions for certain phases of the operation, the method described by Rappaport And Eichhörn as semiquantitative, can give accurate results and constitute a practical technique for the determination of thallium in toxicological analysis. In this technique, thallium is mineralized and then precipitated in the form of sulphide. Redissolved in HC1, it is oxidized in thallic ion and bound to rhodamine B. The compound is soluble in benzene and possesses a maximum of absorption about 540 mμ. On account of the simplicity of its manipulations, this technique is a good routine method for the determination of thallium in toxicology.
En prenant des précautions toutes particulières pour certaines phases de l'opération, les auteurs montrent que la méthode décrite par Rappaport et eichhörn 1 comme semi-quantitative, peut donner des résultats précis et constituer une technique pratique pour le dosage du thallium en analyse toxicologique. Dans cette technique, le thallium est minéralisé puis précipité sous forme de sulfure. Redissous dans HC1, il est oxydé en ion thallique et complexé à la rhodamine B. Le complexe est soluble dans le benzène et possède un maximum d'absorption vers 540 mμ. Par le caractère simple de ses manipulations, elle fournit une bonne méthode de routine pour le dosage du thallium en toxicologie.
