Yield of indirect strand breaks (SBs) (top panels) and ratio of indirect base damages (BDs) and SBs (bottom panels) for the three DNA geometry models (from left-to-right cylinder sector, half-cylinder and sphere) for protons (green shading and left to the vertical dashed line) and alpha particles (red shading and right to the vertical dashed line) for various probabilities P_int,backbone for a ^•OH to react with a backbone. The right panel shows both quantities when an adjusted probability, as indicated in Table 1, is utilized for each geometry.