Focusing high-energy heavy ion microbeam system at the JAEA AVF cyclotron

Performance of a focusing high-energy heavy ion microbeam system in TIARA facility of JAEA Takasaki was tested for the spatial resolution and for the hitting accuracy at a target. A 260 MeV 20Ne7+ ion beam was successfully extracted from the JAEA AVF cyclotron (K = 110) with the smallest momentum spread (ΔP/P = δ) at present. The beam was focused by the microbeam lens system, and a spatial resolution of 260 MeV 20Ne7+ microbeam was measured from a secondary electron image of a Cu grid which had sharp edges, and the hitting accuracy was estimated using single ion hitting onto a CR-39 film. From those two methods of measurement, both the spatial resolution and the hitting accuracy were evaluated at less than 1 μm.