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Rabus, H. (2013). Ionization cross section data of nitrogen, methane, and propane for light ions and electrons and their suitability for use in track structure simulations. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics, 88 (4), 043308-1-043308-21.Ionization cross section data of nitrogen, methane, and propane for light ions and electrons and their suitability for use in track structure simulations AbstractTrack structure Monte Carlo simulations are frequently applied in micro-and nanodosimetry to calculate the radiation transport in detail. The use of a well-validated set of cross section data in such simulation codes ensures accurate calculations of transport parameters, such as ionization yields. These cross section data are, however, scarce and often discrepant when measured by different groups. This work surveys literature data on ionization and charge-transfer cross sections of nitrogen, methane, and propane for electrons, protons, and helium particles, focusing on the energy range between 100 keV and 20 MeV. Based on the evaluated data, different models for the parametrization of the cross section data are implemented in the code PTRA, developed for simulating proton and alpha particle transport in an ion-counting nanodosimeter. The suitability of the cross section data is investigated by comparing the calculated mean ionization cluster size and energy loss with experimental results in either nitrogen or propane. For protons, generally good agreement between measured and simulated data is found when the Rudd model is used in PTRA. For alpha particles, however, a considerable influence of different parametrizations of cross sections for ionization and charge transfer is observed. The PTRA code using the charge-transfer data is, nevertheless, successfully benchmarked by the experimental data for the calculation of nanodosimetric quantities, but remaining discrepancies still have to be further investigated (up to 13% lower energy loss and 19% lower mean ionization cluster size than in the experiment). A continuation of this work should investigate data for the energy loss per interaction as well as differential cross section data of nitrogen and propane. Interpolation models for ionization and chargetransfer data are proposed. The Barkas model, frequently used for a determination of the effective charge in the ionization cross section, significantly underestimates both the energy loss (by up to 19%) and the mean ionization cluster size (up to 65%) for alpha particles. It is, therefore, not recommended for particle-track simulations. Track structure Monte Carlo simulations are frequently applied in micro-and nanodosimetry to calculate the radiation transport in detail. The use of a well-validated set of cross section data in such simulation codes ensures accurate calculations of transport parameters, such as ionization yields. These cross section data are, however, scarce and often discrepant when measured by different groups. This work surveys literature data on ionization and charge-tra...

Total scattering cross sections of the rare gases He, Ne and Ar have been measured, for electrons in the energy range from 4 eV to 2 keV. The measurements were performed using a linear transmission device and an electron energy analyser, with an angular resolution better than 1.1 × 10−3 sr and with an energy resolution far below the first excitation threshold in the three atoms. The uncertainties of the experimental results are generally smaller than 3%. With a few exceptions, the present results are in good agreement with the data of other authors. Systematic deviations were found between the present results and the data available for the total scattering cross sections of He at high electron energies. The deviations increase with increasing energy and reach about 13% at 2 keV. It appears that different levels of the separation of forward-scattered electrons are responsible for these systematic deviations.

Low-energy (E0=65eV) electron-impact single ionization of Ne (2p) has been investigated to thoroughly test state-of-the-art theoretical approaches. The experimental data were measured using a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission energies ranging from 2 to 8 eV, and projectile scattering angles ranging from 8.5^∘ to 20.0^∘. The experimental triple-differential cross sections are internormalized across all measured scattering angles and ejected energies. The experimental data are compared to predictions from a hybrid second-order distorted-wave Born plus R-matrix approach, the distorted-wave Born approximation with the inclusion of postcollision interaction (PCI), a three-body distorted-wave approach (3DW), and a B-spline R-matrix (BSR) with pseudostates approach. Excellent agreement is found between the experiment and predictions from the 3DW and BSR models, for both the angular dependence and the relative magnitude of the cross sections in the full three-dimensional parameter space. The importance of PCI effects is clearly visible in this low-energy electron-impact ionization process