Depth profiles of energy deposition near incident surface irradiated with swift heavy ions

Systematic trend of nm-scale energy deposition depth profiles near incident surface owing to irradiation by swift heavy ions in the energy range of 1-40 MeV/n is explained by track-structure calculation. To explain the trend, the depth profiles of energy deposition by protons and heavy ions in liquid water were calculated by the trackstructure simulation code RITRACKS. The calculation shows that the energy deposition at the incident surface is 40% less than that in the depth, and energy deposition builds up in the first 3 nm, reaching equilibrium. The energy deposition depth profiles owing to different ions are almost scalable. This trend is almost independent from the incident ion species or energy because the energy deposition near the surface is attributed to the deltarays below 500 eV regardless of the incident ion species and energy.