Non-dissociative and dissociative ionization of N₂, CO, CO₂, and CH₄by impact of 50-6000 keV protons and antiprotons

Abstract

Measurements of the cross section for non-dissociative single ionization and the cross sections for the creation of charged fragments have been performed for 50-6000 keV antiproton and proton impact on N2, CO, CO2, and CH4. The results support the understanding of the ionization phenomenon that has been achieved via measurements with fundamental charged particles on atoms. The present high-energy antiproton fragmentation data supply a stringent test of the validity of the published electron-impact fragmentation data which, unfortunately, most of them fail.

Ionization cross section data of nitrogen, methane, and propane for light ions and electrons and their suitability for use in track structure simulations

“…Figure 3 illustrates that the data of energies above 80 keV are generally in good agreement within the experimental uncertainties (which were between 10% and 25%). The measurements of Knudsen et al [31] differ by less than 10% from those of the other groups (no uncertainty was provided), with the exception of the two lowest energy data points. Knudsen et al determined the single-ionization cross sections by measuring the yield of positively charged fragments produced after the passage of a proton through a low-density gas.…”

“…Knudsen et al determined the single-ionization cross sections by measuring the yield of positively charged fragments produced after the passage of a proton through a low-density gas. This yield was then corrected for the fraction of hydrogen atoms produced [29] 50-300 De Heer et al [30] 10-140 Knudsen et al [31] 50-6000 Rudd et al [32] 5-5000 Ionization cross section, H 0 Puckett et al [15] 150-400 Equilibrium fractions of hydrogen charge states Allison [33] Models Rudd model [28] (see Appendix C) Green model [34] (see Appendix D) Table II for references). Electron ionization cross sections were calculated by the BEB model [19] for comparison (the x axis of these data was multiplied by the ratio of proton mass m p to the electron-projectile mass m proj such that data for particles of the same velocity are compared).…”

“…These cross section data for both protons and alpha particles, which are required for particle-track simulations, were obtained from those of methane (largely available) by using a scaling procedure. [36] 1-12.0 Knudsen et al [31] 0.5-6.0 Luna et al [37] 0.5-3.5 Lynch et al [38] 0.25, 1, and 2 Rudd et al [32] 0.005-5.0 Model Rudd model [28] (see Appendix C)…”

“…The same kind of measurement was applied by Knudsen et al [31] to determine the single-ionization cross section. The authors normalized their data to those of electron-impact cross sections in order to obtain absolute cross section values.…”

Gross and partial ionization cross sections in 6-MeV/amu bare-ion collisions with methane

“…We have studied ionization of rare gases, hydrocarbons, and water in collisions of 6 MeV/amu bare-ions by measurements of absolute cross sections and relative intensities of secondary ions. Ionization processes of CH 4 , -C 3-6+ [2], 1-12 MeV protons [3], up to 3keV electrons [4], 50-6000keV protons and antiprotons [5], and 0.5-3.5 MeV proton and electron [6]. However, a limited number of experiments have been reported in collisions of energetic highlycharged ions.…”