An improved internal Cu 3As-alloy cyclotron target for the production of 75Br and 77Br and separation of the by-product 67Ga from the matrix activity

Abstract

The use of Cu 3As-alloy in high current irradiations in an internal target system for the production of 75Br via the 75As( 3He, 3n) 75Br reaction and 77Br via the 75A(α, 2n) 77Br process has been optimized. Radiobromine is separated from the irradiated alloy by thermochromatography and is of high chemical purity. The major radionuclidic impurity in 75Br is 76Br (5–8% at EOB). Batch yields amount to 200 mCi 75Br (EOB) and 48 mCi 77Br (EOB). A wet chemical method based on cation-exchange chromatography followed by solvent extraction was developed to separate 67Ga (formed via the 65Cu(α, 2n) 67Ga reaction) from the matrix activity. The final product is chemically pure but contains 2.3% 66Ga as radionuclidic impurity. The batch yield amounts to 9mCi 67Ga (at 100 h after EOB). The process is of interest only in combination with the production of 77Br where 67Ga is formed as a by-product.