Any pair of the three final state particles (i.e. the scattered projectile, the ejected electron, and the recoiling target ion) can be detected.
The first kinematically complete experiment on single ionization was performed for electron impact.
As a result, the projectile scattering as well as the projectile energy loss relative to the initial energy are by many orders of magnitude smaller than for electron impact and are not measurable with standard techniques for fast heavy ions.
[3] For proton impact at much smaller energy kinematically complete experiments were also performed by momentum-analyzing the scattered projectiles and the recoil ions.
Studies on double ionization and transfer-ionization revealed the important role of electron-electron correlation effects in processes involving multiple electrons.