title: Stochastic radial dose distributions and track structure theory.
abstract: Measured single-event distributions of the specific energy deposited in cylindrical volumes with simulated diameters down to 150 nm for (4)He and (12)C ions with energies of 25 MeV/nucleon and (16)O ions with 21 MeV/nucleon and radial distances up to 12 microm are presented. The mean specific energy per ion <z(r)>, the mean specific energy per target hit z(1)(r), and the relative frequency of target hits nu(r) as a function of radial distance are evaluated and compared with the corresponding quantities of the track structure model of Kiefer and Straaten (Phys. Med. Biol. 31, 1201-1209, 1986). Though there are some discrepancies in the absolute values, the radial dependence of <z(r)>, z(1)(r) and v(r) for (12)C and (16)O ions is reproduced satisfactorily. The model fails to describe the data for (4)He ions. A more detailed comparison of the radial shape of the mean specific energies calculated from the experimental data from the present work and data from the literature reveals a significant projectile charge dependence which is not included in track structure models.
authors.affiliation: Hahn-Meitner-Institut Berlin GmbH, Bereich Festkörperphysik, Glienicker Strasse 100, D-14109 Berlin, Germany.
authors.forename: J U
authors.initials: JU
authors.lastname: Schmollack
authors.forename: S L
authors.initials: SL
authors.lastname: Klaumuenzer
authors.forename: J
authors.initials: J
authors.lastname: Kiefer
mesh_terms: D002244:Carbon; D006371:Helium; D007554:Isotopes; D010100:Oxygen; D011336:Probability; D011829:Radiation Dosage
chemical_list: D007554:Isotopes; D006371:Helium; D002244:Carbon; D010100:Oxygen