Title Inelastic collision processes of low energy protons in liquid water Author(s) Date, H.; Sutherland, K.L.; Hayashi, T.; Matsuzaki, Y.; Kiyanagi, Y. Radiation Physics and Chemistry, 75(2), 179-187 Citation https://doi.org/10.1016/j.radphyschem.2005.10.002 Issue Date 2006-02 Doc URL http://hdl.handle.net/2115/7380 Type article (author version) File Information RPC75_2.pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP Inelastic collision processes of low energy protons in liquid water H. Date*, K.L. Sutherland1, T. Hayashi1, Y. Matsuzaki2, Y. Kiyanagi2 School of Medicine, Hokkaido University, Sapporo 060-0812, Japan 1Japan Science and Technology Agency, Tokyo 105-6218, Japan 2Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan Abstract Production probabilities of ion and excited particle species along the proton beam track in liquid water are estimated around the Bragg peak region, taking into account charge changing processes and energetic secondary electron (δ-ray) behavior. Ionization and excitation processes are divided into two categories in this study: primary processes associated with direct proton (or hydrogen) interaction and secondary processes arising from the electrons ejected by the primary process. We show that the number of events in the secondary processes producing ions and excited particles is larger than that of the primary processes around the Bragg peak while neutralized protons (i.e., hydrogen) with low energy have a large contribution to direct ionization. Effects of charge changing processes on ionization and excitation are also discussed. Key words: proton Bragg peak, inelastic collision, δ-ray, charge transfer, cross sections, liquid water *Corresponding author: Department of Health Sciences, School of Medicine, Hokkaido University N12-W5, Kitaku, Sapporo 060-0812, JAPAN Phone#: +81-11-706-3423 Fax#: +81-11-706-4916 E-mail:
[email protected] 1.