Momentum spectroscopy of electrons lost by light projectiles in collisions with neon targets - art. no. 022714

摘要

Absolute doubly differential electron-loss cross sections were measured for H-0, H-2(+), D-0, D-2(+), He-0, and He+ on neon at 0.1 and 0.5 MeV/amu in order to investigate the velocity dependence and any projectile dependence of the electron spectra. An additional measurement of target ionization in 0.1 MeV/amu Ne-0+He collisions in comparison with electron loss from 0.1 MeV/amu He-0+Ne was aimed at testing the method of "inverse kinematics" for a collision system where the electron angular distribution is dominated by a distinct Ramsauer-Townsend minimum. The measured absolute singly differential cross sections, transformed to the neon frame of reference, agree well over the whole angular range (0 degrees-180 degrees), thereby establishing this as a useful method when high-energy beams of a particular projectile are not readily available. Calculations using both the on-shell and off-shell version of the electron impact approximation show that the quasielastic scattering theory is rather poor at such low collision velocities, but nevertheless reveal the importance of doubly inelastic processes in the case of both He-0 and He+ ionization. Satisfactory agreement between theory and experiment was obtained at the higher velocity. The H-2(+) and D-2(+) results show evidence of molecular effects. [References: 32]