Double-ionization mechanisms and asymmetry parameters for (e,3e-1e) reactions

In this work the cross section for the coincident detection of two electrons following double ionization of helium by fast electrons is analyzed. Structures arising in cross sections are associated with ionization mechanisms. The role of electronic correlations is elucidated. The theory is compared with available experimental data and suggestions for future experiments are made where results can be analyzed in terms of generalized asymmetry parameters and directly linked with well studied asymmetry parameters for double photoionization. Further, a method of calibrating relative (e,3e-1e) cross sections to double photoionization cross sections is proposed.