RESUMO
This paper describes a procedure for the validation of alpha-particle sources (exempt unsealed sources) to be used in experimental setups with liquefied gases at cryogenic temperatures (down to -196 °C) and high vacuum. These setups are of interest for the development and characterization of neutrino and dark matter detectors based on liquid argon, among others. Due to the high purity requirements, the sources have to withstand high vacuum and cryogenic temperatures for extended periods. The validation procedure has been applied to 241Am sources produced by electrodeposition.
RESUMO
Accurate dating of samples by alpha spectrometry presupposes that the dated system behaved as closed and that no allochthonous (232)Th was provided to the system. Therefore the selection of appropriate samples is a fundamental task that will determine the reliability and accuracy or not of the results. In this paper, by means of a thorough characterisation, those petrological and chemical variables that allow the preselection of the most suitable samples to be dated have been identified and used to calculate the sample quality index.