Small-angle scattering in stripping collisions of hydrogen atoms having energies of 1-10 keV in various gases

Abstract

Angular distributions of protons resulting from stripping collisions of neutral hydrogen atoms in the ground state with He, Ar, Kr, ${\mathrm{H}}_2$, ${\mathrm{N}}_2$, ${\mathrm{O}}_2$, ${\mathrm{H}}_2$O, C${\mathrm{O}}_2$, and ${\mathrm{C}}_6$ ${\mathrm{H}}_6$ have been measured for beam energies $E$ between 1-10 keV and angles of up to 7°. They are found to be strongly peaked in forward direction. Where known, total stripping cross sections were used to derive absolute differential cross sections $\frac{d\sigma }{d\Omega }$. For a given gas, the distribution widths vary roughly proportional to $\frac{1}{E}$. The product of beam energy and the half-cone angle ${\theta }_{50}$ into which 50% of all protons are scattered varies from approximately 0.5 keV deg for ${\mathrm{H}}_2$ to approximately 1.7 keV deg for Kr and ${\mathrm{C}}_6$ ${\mathrm{H}}_6$. For the atomic target gases, deduced normalized differential cross sections $\rho =\theta sin\theta \frac{d\sigma }{d\Omega }$ as functions of $E\theta$ agree in shape roughly with those derived for elastic scattering of hydrogen atoms. The impact parameters corresponding to ${\theta }_{50}$ are estimated. The significance of the peaking in forward direction is investigated.