The double differential cross section for electron capture to the continuum in the strong-interaction region: fast, highly charged ions on helium atoms

Abstract

The double differential cross section for electron capture to the continuum in collisions of highly charged, fast ions with helium was measured. The parameters that describe the multipole content of the electron distributions were extracted. The monopole term shows a weaker dependence on ion charge and velocity than that observed for perturbative collisions. The dipole (asymmetry) term scales with the ion energy per nucleon divided by the ion charge. At the lowest values of this parameter investigated in this work, a rather large quadrupole term is needed to describe the cross section.