Development of a tandem generator system 229Th/225Ac/213Bi for repeated production of short-lived α-emitting radionuclides

229Th was isolated from a long-stored 233U sample using an anion exchanger and 8 M HCl. Thorium was separated from macroamounts of inactive impurities on an anion exchanger in aqueous-methanol HNO3 solutions. A tandem generator system was developed for repeated isolation of 225Ac (α, 10 days) from the parent radionuclide 229Th (7.3 × 103 years) sorbed on an anion-exchange column, with the subsequent sorption of Ac on a cation-exchange column and repeated elution of 213Bi (α, 45.6 min) with dilute HCl and HBr solutions. The γ-ray spectra of the radionuclides at various steps of their isolation are presented. Alternative procedures for production and isolation of 225Ac and 213Bi are described. The application potential and advantages of the newly developed tandem generator system are discussed.