Study of electron capture reactions by means of double translational spectroscopy

The technique of double translational spectroscopy is applied in order to study electron capture by state-selected multiply charged ions. The projectile ions are prepared in specific atomic states by electron capture in an initial gas target with succeeding energy analysis. The studied capture reaction takes place in a second collision chamber. The final-state population being measured by the energy gain of the projectile ions. The advantages of this method as well as new experimental possibilities are discussed by means of the collision systems Ar 3+( * ) -Ar and Ar 2+( * ) -He, Ne.