Production of 225Ac and 223Ra by irradiation of Th with accelerated protons

• Published in: Radiochemistry (New York, N.Y.) N.Y.), 2011-02, Vol.53 (1), p.73-80
• Main Authors: Zhuikov, B. L., Kalmykov, S. N., Ermolaev, S. V., Aliev, R. A., Kokhanyuk, V. M., Matushko, V. L., Tananaev, I. G., Myasoedov, B. F.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Nuclear Chemistry
• ISSN: 1066-3622; 1608-3288
• DOI: 10.1134/S1066362211010103

The possibility of producing 225 Ac and 223 Ra by irradiation of natural 232 Th with medium-energy protons was examined. Thorium foils were irradiated with 90-, 110-, and 135-MeV protons at the accelerator of the Institute for Nuclear Research, Russian Academy of Sciences, in Troitsk (Moscow oblast). The cumulative production cross sections for 225 Ac were 6.7 ± 0.9, 9.8 ± 1.9, and 13.9 ± 1.5 mb, and for 227 Th ( 223 Ra precursor), 43 ± 5, 37 ± 6, and 35 ± 4 mb, respectively. Based on the experimental data and theoretical calculations, the possible yields of 225 Ac and 223 Ra in irradiation of thick thorium targets at various accelerators were determined. An efficient procedure was suggested for isolating the products from the irradiated targets: 225 Ac, by liquid extraction and extraction chromatography, and 223 Ra, by sublimation from a thorium-lanthanum melt followed by thermochromatographic separation in metallic titanium columns and extraction-chromatographic isolation of radium. The procedure allows production of large (units of curies) amounts of radiochemically pure 225 Ac and 223 Ra, which is promising for wide use of these radionuclides in nuclear medicine.