Coupling the Coplanar (e,2e) Geometry to the Perpendicular Plane Geometry

Abstract

Experimentally determined absolute (e,2e) differential cross sections are presented for ionisation from a helium target, in which the two outgoing electrons have the same energy and the same scattering angle with respect to the incident beam. Results are presented for two incident electron energies, 20eV and 40eV above the ionisation threshold. The detection plane defined by the outgoing electrons was varied from being coplanar with the incident beam to being perpendicular to the beam. The spectrometer used to collect these results is fully computer controlled and real-time computer-optimised.