  We explore excitation and ionization by neutron impact as a novel tool for
the investigation of electron-electron correlations in helium. We present
single and double ionization spectra calculated in accurate numerical ab-initio
simulations for incoming neutrons with kinetic energies of up to 150 keV. The
resulting electron spectra are found to be fundamentally different from
photoioniza- tion or charged particle impact due to the intrinsic many-body
character of the interaction. In particular, doubly excited resonances that are
strongly suppressed in electron or photon impact become prominent. The ratio of
double to single ionization is found to differ significantly from those of
photon and charged particle impact.
