Characterization of MIRCOM, IRSN’s new ion microbeam dedicated to targeted irradiation of living biological samples

Ion microbeams have emerged as a powerful tool in several domains of radiation biology, from the evaluation of environmental and occupational risks of exposure to low doses of ionizing radiation, to the study of temporal evolution of DNA damage and repair after irradiation of targeted (sub)cellular components. This paper reports the development and commissioning of the IRSN’s MIRCOM facility designed for targeted irradiation of living biological samples with a focused ion microbeam extracted in air. This equipment is able to provide protons, alpha particles, and heavier ions such as B, C, O, with energies up to a few MeV. Its performances have been assessed, in a first step, with 4 MeV protons. The beam spot size has been evaluated on CR39 track detectors and living cells at 2.2 ± 0.3 µm, and the targeting accuracy of the system has been measured using online time-lapse imaging at 2.1 ± 0.7 µm.