Development of 115 Cd/115m In generator for industrial and environmental applications

Abstract

Indium isotopes, 111In, 113In and 115In are widely used as radiotracers in industrial and environmental applications. 113mIn generators can be found in the international market. However they are manufactured by only a few companies worldwide, they are rated at rather high prices and not always they are available for sale (they are frequently manufactured only upon request). Hence it is of interest to produce the equipment in the country in which it will be used, especially if the parent nuclide can be also produced there. In Brazil, for instance, the ideal situation would be to produce a 115Cd/115mIn generator, whose precursor is 114Cd. The irradiation conditions of the isotopically enriched 114CdO target were defined according with the neutron flux provided the by a IPR-R1 TRIGA reactor and the nuclear properties of the target. Column experiments were performed with the 115Cd/115mIn pair. The parent and daughter nuclides were separated percolating the eluate containing the chemical species Cd2+ and In3+ through two ion exchange resins, Ag11A8 and Dowex 1x8. 1.0 mol/L HCl and 2 mol/L HCl + 0.1 mol/L NH4Cl solutions were tested as the eluent. Analyses were accomplished by gamma spectrometry to determine the presence of 115Cd and 115mIn nuclides in the eluted fractions. Further tests using non-enriched and inactive CdO were performed to confirm the results. The amount of eluted Cd2+ and In3+ was determined by ICPAES. Tests using resin Ag11A8 and 1.0 mol/L HCl eluent solution resulted in 100 % adsorption of the Cd2+ and nearly 50 % elution of In3+, corresponding to the best conditions for elution.