Cross Section Measurements Of Eu-151(He-3,5n) Reaction: New Opportunities For Medical Alpha Emitter Tb-149 Production

Method for production of alpha emitter Tb-149 by irradiation of Eu-151 with 70 MeV He-3 nuclei is proposed. For the first time, the cross sections for the formation of isotopes Tb-149,Tb-150,Tb-151,Tb-152 were measured experimentally using a stack foil technique in the He-3 particles energy range 70 -> 12 MeV. The thick target yield of Tb-149 is 39 MBq/mu Ah, or 230 MBq/mu A Tb-149 at saturation. The optimal energy range from the point of view of radioisotopic purity is 70 -> 40 MeV. At these conditions about 150 MBq/mu A Tb-149 can be produced in 8 hours irradiation, which is sufficient for therapeutic applications. The main impurities are Tb-150 (similar to 100% in activity) and Tb-151 (similar to 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 Tb-149 from the bulk target material.