Absolute helium (e,2e) differential cross sections have been measured over a more general range of directions of the outgoing electrons than has previously been attempted and at an incident energy for which all the complexities of exchange and capture processes, incoming and outgoing channel distortions, and short- and long-range correlations are present.

• Received 24 August 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.2912