  Secondary electron cascades can induce significant ionisation in condensed
matter due to electron-atom collisions. This is of interest in the context of
diffraction and imaging using X-rays, where radiation damage is the main
limiting factor for achieving high resolution data. Here we present new results
on electron-induced damage on liquid water and ice, from the simulation of
Auger electron cascades. We have compared our theoretical estimations to the
available experimental data on elastic and inelastic electron-molecule
interactions for water and found the theoretical results for elastic cross
sections to be in very good agreement with experiment. As a result of the
cascade we find that the average number of secondary electrons after 100 fs in
ice is about 25, slightly higher than in water, where it is about 20. The
difference in damage between ice and water is discussed in the context of
sample handling for biomolecular systems.
