High-energy electron experiments. I. Total and differential cross-sections for multiple ionization

The role of electron correlation in multiple ionization has been studied extensively by means of high-energy electron experiments. Some aspects of this work are discussed. Firstly, the ratio of total cross-sections for single and multiple ionization is considered in relation with the corresponding ratio for photon impact. Secondly, differential measurements of multiple ionization of the noble gases, as obtained in electron--ion coincidence experiments, are reviewed and compared with recent photon impact results and calculations