Quantitative measurements of small isotopic samples in gaseous mixtures by utilization of some nuclear properties

The question is to define the characteristics of a group of measurements allowing the analysis of traces of radioactive rare gases in gas mixtures of different composition. To distinguish the radioactive isotopes from each other and the activity level reaching 106 due to their nuclear properties, the method was chosen to use several nuclear properties: gamma radiation energy, beta particle energy, lifetime of excited states. The choice of a plastic scintillator as beta detector allows to answer satisfactorilly to this demand by measurement of nuclear constants because of the short de/excitation time of this detector. Another advantage is that it can be a reservoir for the sample without any destruction nor modification of the sample. The study has been based on the mixture of Kr-85, the analysis of other rare gases follwos immediately from the adopted principle