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

Method for production of alpha emitter 149Tb by irradiation of 151Eu with 70 MeV 3He nuclei is proposed. For the first time, the cross sections for the formation of isotopes 149,150,151,152Tb were measured experimentally using a stack foil technique in the 3He particles energy range 70 → 12 MeV. The thick target yield of 149Tb is 39 MBq/μAh, or 230 MBq/μA 149Tb 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 149Tb can be produced in 8 hours irradiation, which is sufficient for therapeutic applications. The main impurities are 150Tb (~100% in activity) and 151Tb (~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 149Tb from the bulk target material.