Ac-225 is a crucial isotope for targeted alpha therapy, yet its clinical application is severely constrained by supply shortages. The use of high-intensity proton beams from linear accelerators to irradiate Ra-226 targets offers a viable approach to significantly enhance Ac-225 production. However, excessive proton energies, while increasing yield, promote the generation of impurity isotopes such as Ac-227, complicating chemical separation and raising both production costs and radiological concerns.This study employs Geant4 Monte Carlo simulations with a detailed model that includes the beam window, target, and encapsulation structure. By systematically simulating nuclear reactions across various energy levels, we quantified the production yields of Ac-225 and its impurities. An optimal proton energy was identified that maximizes Ac-225 yield while effectively controlling impurity levels, providing key insights for efficient large-scale Ac-225 production.

The global adoption of targeted alpha therapy (TAT) using actinium-225(²²⁵Ac)-labeled radiopharmaceuticals is rapidly expanding, driving an urgent need to scale up ²²⁵Ac production and improve supply reliability. Among potential production methods, accelerator-based high-energy proton irradiation of thorium-232(²³²Th) targets via the ²³²Th(p,x)²²⁵Ac reaction represents a promising and sustainable approach. However, achieving large-scale ²²⁵Ac production through this route requires addressing key technological challenges, including the development of high-power proton beams (100–150 MeV) and robust targetry systems. To address these challenges, the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS), is constructing a dedicated demonstration facility—the Isotope Pharmaceutical production platform based on Superconducting Accelerator Facility for Effective therapy (IP-SAFE). Powered by a state-of-the-art Superconducting Radio Frequency (SRF) linear accelerator, this advanced facility will deliver a high-performance 115 MeV Continuous Wave (CW) proton beam with an intensity of 0.5–1 mA to irradiate ²³²Th targets. This paper provides an overview of the IP-SAFE project, highlights the recent progresses.

Ac-225 is a crucial isotope for targeted alpha therapy, yet its clinical application is severely constrained by supply shortages. The use of high-intensity proton beams to irradiate Ra-226 targets offers a viable approach to significantly enhance Ac-225 production, as it enables higher yields and greater scalability. However, the process is also accompanied by the generation of other isotopes of actinium, especially the long-lived Ac-227, which challenges the purification process. This work establishes a precise parameterized model that correlates beam energy, target thickness, and cooling time with each other for optimizing Ac-225 production while minimizing Ac-227 impurity levels and target material consumption. We determine the optimal parameters, which effectively maximize Ac-225 yield while controlling impurity levels and target material consumption. This method provides a valuable reference for the efficient production of Ac-225

The Arronax C70XP cyclotron is used to extract positive ions at fixed energy and protons from 35 to 70 MeV for irradiations. In order to support lower energy irradiations, an internal target system that can be positioned at various radius is being built. Several studies are being performed to investigate the beam behaviour. These studies include intensity profile of the beam as a function of the radius and the impact of several magnet settings. Multiple repetitive checks have also been done and a first operational protocol is being favored to minimise potential impact on the final results for short irradiation in the R&D phase. This phase is part of a more global study that will tackle for example production of Astatine 211 at high intensity. The ongoing work is reported within this paper.