Stopping Power of Liquid Water for Low-Energy Electrons

Abstract

The dielectric function e(q, ω) for liquid water is determined from an insulator model with parameters fixed by available optical data. Ionization of the oxygen K shell is described by generalized oscillator strengths. This model dielectric function is used to calculate the stopping power of liquid water for electrons with energies from 10 eV to 10 keV. The results agree well in the common energy range with an existing tabulation for 256 eV ≤ E ≤ 10.2 MeV and with Bethe-theory predictions down to 200 eV. The peak in stopping power at ∼120 eV is ∼25% lower than the predictions of R. H. Ritchie, R. N. Hamm, J. E. Turner, and H. A. Wright (in Proceedings, Sixth Symposium on Microdosimetry, Brussels, Belgium (J. Booz and H. G. Ebert, Eds.), pp. 345-354, Commission of the European Communities, Harwood, London, 1978 [EUR 6064 d-e-f]).