study of $^{225}$Ac production cross section by proton, deuteron, and neutron irradiation on $^{232}$Th targets based on FLUKA toolkit

he limited global supply of actinium-225 remains a major bottleneck for its widespread clinical application in targeted alpha therapy, highlighting the importance of exploring alternative methods for large-scale production. In this study, the FLUKA Monte Carlo transport code was employed to simulate the irradiation of thorium targets with protons, neutrons, and deuterons in the energy range of 10 to 800 MeV per nucleon. The production cross sections of $^{225}$Ac for different incident particles were systematically compared to identify the most promising production pathway for accelerator-based synthesis. Additionally, the study reports product cross section data for relevant actinides, thorium, radium, and protactinium isotopes. By comparing the simulated results with available experimental data, the reliability of the nuclear reaction models was verified, and directions for further refinement of Monte Carlo-based physical models in radionuclide production simulations were proposed.