Differential Cross Sections for Electron-Impact Single and Double Ionization of Helium

Correlated quantal three-body and four-body dynamics are studied in the electron-impact single and double ionization of Helium. Calculations are made using non-perturbative 6D and 9D time-dependent close-coupling codes adapted for massively parallel computers. Theoretical calculations of triple differential cross sections for single ionization of Helium and pentuple differential cross sections for double ionization of He are compared with recent low-energy reaction microscope experiments.