Measurements of Large-Angle Single Collisions between Helium, Neon, and Argon Atoms at Energies to 100 kev

Single collisions between ions and atoms have been studied at 25, 50, and 100 kev energies for the cases ${\mathrm{He}}^{+}$ on He, ${\mathrm{He}}^{+}$ on Ne, ${\mathrm{He}}^{+}$ on A, ${\mathrm{Ne}}^{+}$ on Ne, ${\mathrm{Ne}}^{+}$ on A, and ${\mathrm{A}}^{+}$ on A. The incident ion beam traversed a collision chamber containing a target gas whose pressure was maintained low enough to insure single interactions. The particles, which were scattered at each angle from four to forty degrees, passed through a pair of collimating holes with a resolution width of one degree. An electrostatic analyzer and its associated detectors determined the number of scattered atoms in each state of charge, ranging from zero to seven times ionized. The percentages of the various charge states in the scattered beam are plotted in order to indicate the dependence of this quantity on scattering angle and energy for each of the systems studied. The differential cross section for the scattering of particles has also been measured in each case and compared with values calculated classically from a Coulomb potential energy function modified by exponential screening.