Millipede – A new facility for particle beam radiobiology research

We present Millipede, a new facility for particle radiobiology research at the 6MV Tandetron accelerator at the Helmholtz-Center Dresden-Rossendorf. The setup was developed for in vitro irradiation with multiple ion species over a broad linear energy transfer (LET) range and combines microscopy-based sample positioning, scanned field delivery, and downstream single-particle detection. Its performance was evaluated using clonogenic survival and γH2AX/53BP1 immunofluorescence staining after irradiation with 10 MeV protons, 16 MeV helium, and 35 MeV boron ions. Additional proof-of-principle foci measurements were performed with lithium and carbon ions. The biological data showed clear LET-dependent trends. Proton irradiation produced survival characteristics like the X-ray reference, while helium and boron ions had steeper survival curves and increased biological effectiveness. DNA damage foci imaging showed increasingly clustered damage patterns with increasing LET. These results demonstrate the feasibility and reproducibility of radiobiological experiments at Millipede and establish the beamline as a robust platform for future particle beam research.