Feasibility of a novel photoproduction of (225)Ac and (227)Th with natural thorium target

We propose an innovative way to produce both (225)Ac and (227)Th, two precious radioisotopes enabling promising targeted alpha therapy, in a natural thorium target bombarded with a 30–90 MeV electron beam. Bremsstrahlung photons in the target are analyzed by MCNP and in-situ photonuclear transmutation of (232)Th is evaluated by using the TENDL nuclear data. In the photo-transmutation analysis, 13 nuclides including (229)Th and (231)Pa are modelled. Special procedures with chemical separations are also proposed to produce pure (225)Ac and (227)Th in separate streams. In addition, performance of the new approach is compared with conventional methods in terms of the (225)Ac and (227)Th yields. After a Th target is bombarded with a 500 kW electron beam for a year, yearly (225)Ac yield is ~ 8.47 GBq (semi-permanently) and yearly (227)Th yield is ~ 48.9 GBq over 50 years, and their yields are at least doubled in a 2-year irradiation. This work will help increase global supply of the two precious isotopes and would invariably help advance TAT-related researches and developments.