3D-cross sections for argon single ionization by 200 eV electron impact

Using a multi-particle momentum spectrometer (reaction microscope), three-dimensional and fully differential cross sections for electron impact ionization were obtained, providing benchmark data for comprehensive tests of theoretical calculations. Since all final-state particles, including the scattered projectile were detected, a good momentum transfer resolution was obtained also for heavy targets like argon. Results for ionization of the 3p-orbital in Argon by 200 eV electron impact are presented. The cross section patterns display rich structure, which are partially reproduced by theory, although differences persist outside the projectile scattering plane.