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 70MeV $^3$He nuclei is proposed. For the frst 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→40MeV. At these conditions about 150 MBq/μA $^{149}$Tb can be produced in 8hours irradiation, which is sufcient 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.