Thermodynamic stability of radioactivity standard solutions.

Optimal thermodynamic stability conditions must prevail when radioactivity standard solutions are prepared. These conditions are studied, they relate to: * The nature of the radioactive ion, which makes it possible to establish the pH of the solubilization medium at a given concentration, * The carrier concentration, which is determined by considering the radionuclide production method and the prior concentration in the original solution from the supplier, * The most stable oxidation state of the radioactive ion and of the carrier ion, which must be considered at the pH established by the solubilization medium. A procedure for all the glassware used in preparation has been implemented.