Predictions of Ac and Ra production cross sections from p, α and heavy ion irradiated thorium and uranium targets.

-This work studies effective methods for producing Ac and Ra by bombarding Th and natural uranium targets with different incident particles. Direct production of Ac via high-energy proton bombardment of Th inevitably contains Ac impurities, complicating the separation and purification processes. In contrast, obtaining Ac through the generated Ra can avoid Ac contamination. Given the low cross section for the proton-thorium reaction to produce Ra, exploring new methods to improve Ra production efficiency is critical. This study utilized several physical models of the Monte Carlo transport codes FLUKA and PHITS to calculate the production cross sections of Ac, Ra, Ra, and Th via the bombardment of thorium and uranium targets with energetic protons, α-particles, Be, and C across an energy range of 10-800 MeV/u. The predicted cross sections were then compared with existing experimental data. The predictions indicate that the energy thresholds to produce Ac, Ra, and Ra via α-particle and heavy ion irradiation are lower than those for proton, and the production cross sections are significantly increased, the incident energy corresponding to the peak cross section is mainly below 100 MeV/u. According to the PHITS JQMD-2.0 results, using α-particle bombardment of thorium targets to produce Ra and subsequently obtaining high-purity Ac may be an efficient production pathway. Moreover, when the α-particle energy is below 100 MeV/u, the predicted cross section of Ra for the natural uranium target is higher than that for the thorium target, suggesting that α-particle bombardment of the natural uranium target could be a potential new method to improve Ac production efficiency. This study provides theoretical reference for subsequent experimental cross section measurement and isotope production.