Theoretical cross sections for electron collisions in water: structure of electron tracks.

To understand what happens when biological matter is irradiated needs a detailed knowledge of the microscopic distribution of interactions and especially of the energy deposited in irradiated matter. Monte Carlo event-by-event simulations are particularly suitable for this task. However, the development of these track-structure codes necessitates accurate interaction cross sections for all the electronic processes: ionization, excitation and elastic scattering. In these conditions, we have recently developed a Monte Carlo code for electrons in water, this latter being commonly used to simulate the biological medium. All the electronic processes are studied in detail via theoretical differential and total cross-section calculations. The purpose of this work is to make an inter-comparison of our cross sections with those used in the electron track-structure codes developed in the literature, and to compare macroscopic quantities such as stopping powers and mean energy transfer distributions to available experimental data and/or to theoretical predictions in liquid water.