The integral cross-section for electron-ion ionization collisions with an optical selection of the target’s quantum state.

We propose a method to measure integral cross sections for electron-ion collisions. The study is focused on the ionization of ions – creating ions of an electric charge higher than one. The technique is based on an electron-bombardment of an optically Doppler-cooled set of calcium ions inside a Paul trap. By analyzing the time dynamics of depletion of the ions, the desired cross-sections can be deduced. The method allows distinguishing the scattering of electrons from the ions in various initial quantum states.

The details of the apparatus and the experimental procedure will be presented. The first, preliminary results will be shown and compared with available experimental and theoretical data sets.