Simultaneous Projectile-Target Ionization: A Novel Approach to (e,2e)-Experiments on Ions

A kinemat ically complete exper iment for simultaneous ionizat ion of pro ject ile and target has been performed for 3.6 MeV/u C2 + on He co llisions measur ing the fina l vector momenta of the He1 + reco il- ion and o f two electrons (project ile, target) in co incidence with the emerging C3 + project ile. The feasibilit y o f an event-by-event separat ion o f the var ious react ion channels, among them the ionizat ion of C2 + by the int eract ion with a quasi-free target electron, is demonstrated in agreement with 6-body CTMC calculat ions, paving the way to kinema tically complete electron-ion scattering experiments. PACS numbers: 34.10+x, 34.50.Fa The ionizat ion o f ions by electron impact is one o f the most fundamental processes in atomic co llis ion phys ics. This react ion has enormous pract ical importance and far-reaching technical consequences for the understanding and modeling o f a ll ast rophysica l as we ll as terrest r ia l plasmas including those in fusion reactors. Whereas total cross-sect ion measurements for ionizat ion a