Ion-Lithium Collision Dynamics Studied with a Laser-Cooled In-Ring Target

We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the ’MOTReMi,’ is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In the inaugural experiment on collisions with $1.5\mathrm{MeV}/\mathrm{amu}$ ${\mathrm{O}}^{8+}$-Li the pure ionization of the valence electron as well as the ionization-excitation of the lithium target was investigated.

Figure 1

The MOTReMi apparatus.

Figure 2

(a) Cross sections of single ionization in $1.5\mathrm{Mev}/\mathrm{u}$ ${\mathrm{O}}^{8+}$-Li collisions as a function of the $Q$-value and the projectile scattering angle ${\theta }_P$. (b) $d\sigma /d{E}_e$ of the same collision system for pure $2s$ ionization (solid squares) and ionization-excitation (open circles). The curves are CDW-EIS results for $2s$ (solid line) and $1s$ (dashed line) ionization. In the shaded range a significant fraction of the electrons is not detected due to acceptance limitations.