The (e,2e) recoil peak to binary peak ratio as a function of the ejected-electron energy is reported for helium autoionizing levels (2p2)1D and (2s2p)1P. A special out-of-plane geometry is used where the ejected electrons are detected in a plane that includes the momentum transfer axis but is perpendicular to the scattering plane. The measured recoil peak to binary peak ratio is a dimensionless quantity that can be directly compared with calculations. A second-order model in the projectile-target interaction correctly reproduces the observed energy dependence and magnitude of the ratio, while a first-order model does not.
Digital Object Identifier (DOI)
deHarak, B. A.; Bartschat, K.; and Martin, Nicholas L. S., "Energy Dependence of the (e,2e) Recoil Peak to Binary Peak Ratio Across He (2p2)1D and (2s2p)1P Autoionizing Levels" (2014). Physics and Astronomy Faculty Publications. 131.