Cross section measurements of 151 Eu( 3 He,5n) reaction: new opportunities for medical alpha emitter 149 Tb production

Method for production of alpha emitter 149 Tb by irradiation of 151 Eu with 70 MeV 3 He nuclei is proposed. For the first time, the cross sections for the formation of isotopes 149,150,151,152 Tb were measured experimentally using a stack foil technique in the 3 He particles energy range 70 → 12 MeV. The thick target yield of 149 Tb is 39 MBq/μAh, or 230 MBq/μA 149 Tb at saturation. The optimal energy range from the point of view of radioisotopic purity is 70 → 40 MeV. At these conditions about 150 MBq/μA 149 Tb can be produced in 8 hours irradiation, which is sufficient for therapeutic applications. The main impurities are 150 Tb (~100% in activity) and 151 Tb (~30% in activity). The proposed method surpasses its counterparts by the high content of the target isotope in the natural mixture and the simplicity of the radiochemical separation of 149 Tb from the bulk target material.