Triple Differential Cross Sections for Electron Impact Ionization of Argon between 50 eV and 215.8 eV

Abstract

The most detailed information about electron impact ionization of atoms is available from (e,2e) experiments in which both electrons following an ionizing event are detected in coincidence. The kinematics of the collision is fully determined and provides the measurement of triple differential cross sections (TDCS). Numerous experiments on helium and on atomic hydrogen performed from threshold to high energy have shown the extreme sensitivity of the coplanar energy sharing symmetric geometry to short-and long-range interactions. At intermediate energy, the TDCS present two maxima interpreted in terms of binary and backscattering processes. Then, the standard DWBA calculations of Whelan et al.¹ reproduce correctly the measurements. When decreasing the incident energy, the two maxima merge into a unique structure; the inclusion of post-collisionnal interaction (PCI) and polarization effects in the standard DWBA calculations is needed to give a correct agreement with the experiments. ^1,2