Inelastic-collision cross sections of liquid water for interactions of energetic protons

Cross-section data for inelastic interactions of energetic protons with liq uid water, for use, e.g. as input in track structure analysis, are derived for an energy range from 0.1 keV to 10 GeV. At proton kinetic energies abov e about 500 keV, the first Born approximation and the dielectric-response f unction determined earlier are used. At proton energies above several hundr ed MeV in particular, the Fermi-density effect is also incorporated. At ene rgies below about 500 keV, which corresponds to a residual range of about 8 .9 x 10(-6) m, cross-section values are derived semiempirically by an exten sive and critical analysis of experimental and theoretical information conc erning not only cross sections for individual processes such as ionisation, excitation, and charge transfer but also stopping power and other relevant quantities. Spectra of secondary electrons resulting from ionising collisi ons are also presented. The analysis also includes considerations of phase effects on cross sections. (C) 2000 Elsevier Science Ltd. All rights reserv ed.