Radiation biology on the ANTARES external micro-beam irradiation facility at ANSTO

Abstract This paper presents the observation of DNA double-strand breaks following irradiation using a new setup for cell culture exposure at the Australian Nuclear Science and Technology (ANSTO) External microBeam Irradiation Facility (EBIF). This facility represents the first capability in Australia to perform ion beam irradiation in air, supporting radiobiology research. The core capability of this beamline is its capacity for irradiation of biological samples under ambient conditions (room temperature and atmospheric pressure) while employing ion microbeam to achieve high targeting precision and accurate dose delivery. The MeV-energetic ions used for irradiation, ranging from hydrogen to carbon, oxygen, and heavier ions have variable ranges in water up to 2 mm, depending on the ion species. This makes the beamline suitable for radiobiological studies involving cell cultures, microorganisms, and thin tissue samples. This paper describes the established protocol to prepare and irradiate cell cultures on the EBIF, as well as Monte Carlo simulation and dosimetry. Radiobiological measurements were conducted using human fibroblast cells irradiated on a 75 nm silicon nitride membrane in cell culture media. Post-irradiation DNA double-strand break (DSB) burden was assessed using γH2AX immunocytochemistry demonstrating successful delivery of the proton microbeam to live cells. Finally, this work provides initial results supporting the feasibility of conducting radiation biology research with ion beams for the first time in Australia, with potential relevance to applications in harsh radiation environments, including space, avionics, nuclear, and clinical contexts.