Parametrization of low-energy symmetric (e, 2e) differential cross section measurements

Symmetric (e, 2e) experimental studies on helium over a very wide range of scattering geometries at energies from 1 to 50 eV above the ionization threshold are parametrized in terms of a set of universal irreducible tensorial angular functions. Measurements from the Manchester and Paris experimental groups are used in this parametrization, which provides a complete picture of the symmetric ionization process. The use of the parametrization technique for deconvolution of the experimental angular resolution from measured results is discussed.