Atomic and Molecular Physics at the Cryogenic Storage Ring

The Cryogenic Storage Ring (CSR) at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany is one of the most ambitious projects among the new electrostatic storage facilities. It features a nested vacuum structure with a circumference of 35 m, where the innermost vacuum chambers can be cooled to liquid helium temperature (~4K) by a closed cycle cooling unit. The cryogenic temperatures result in very low residual gas densities inside the experimental chambers (on the order of 10³ cm^-3), as well as a strong reduction of the blackbody radiation field. The electrostatic ion optics allow for storage of positive and negative ions with kinetic energies of up to 300 keV per unit charge, essentially independent of the particle mass.

We will give a brief overview of the experimental capabilities of the CSR and report on recent photodetachment experiments with negative atomic and molecular ions. Furthermore, we will present the results of merged beams experiments of free electrons and neutral atoms with cold molecular ions of astrophysical interest.