A Helium Ion Linear Accelerator Optimised for Astatine Production

This paper presents the design of a linear accelerator optimised for the production of astatine-211, one of the most effective theragnostics isotopes for targeted alpha therapy of cancer (TAT). When attached to a carrier molecule that selectively binds to cancer cells, this powerful alpha emitter enables highly localised cell damage. The 11 m long linac is designed to accelerate an average current of up to 2 mA of fully stripped helium ions to 28.4 MeV, the energy required for 211At production on a bismuth target. The accelerator comprises an alpha particle source, a compact Radio Frequency Quadrupole (RFQ), and a Quasi-Alvarez Drift Tube Linac (QA-DTL). Compared with conventional cyclotron-based solutions, the proposed design provides higher beam current for increased isotope yield, together with reduced beam losses and activation. In addition, compared with a standard Drift Tube Linac (DTL) configuration, the adoption of a QA-DTL structure enables more compact dimensions and improved power efficiency.