Electron Impact Ionization? The Giessen Approach to Cross Sections

Collisions of ions with electrons are a class of fundamental processes and they provide insights into the structure and the dynamics of atomic or molecular systems. Out of these, the electron impact ionization (EII) is one pathway, where the impinging electron knocks out a bound electron from the ionic core. The cross section data for these processes are of vital importance for understanding plasma and in atomic, astrophysical and fusion environments. Comparisons between experimental data and theoretical calculations provide information about the validity of the theoretical framework. This talk will present the experimental setup for measuring absolute EII cross sections in the range of 10 eV to 1000 eV at the Institute for Atomic and Molecular Physics (IAMP) in Giessen. Data for many ion species were obtained in the past. Here, the latest results for Tungsten will be discussed.