Electron capture at low velocity in the collision of Ar¹⁷⁺ ions with atoms, clusters and solids

Absolute x-ray emission has been measured when Ar¹⁷⁺ ions at 255 keV collide either with atomic gaseous targets of Ar or N₂, with Ar clusters or with thin carbon foils. Preliminary results show a strong decrease of the x-ray signal with the backing pressure of the cluster supersonic jet compared to ion-atom interaction. This effect is a clear signature of slow highly charged ions interacting with clusters. Additionally, high resolution x-ray technique gives us access to the charge state distribution of the emitting ions.