Imaging of Neutral Fragmentation Products from Fast Molecular Ion Beams: Paving the Way for Reaction Studies in Cryogenic Environment

The focus of this work are experimental studies on dissociative recombination in merged-beams experiments at storage rings. Dissociative recombination of the sulfur hydride cation (SH+) has been investigated at the magnetic Test Storage Ring (TSR) in Heidelberg, Germany. Measurements of the reaction rate coefficient and momentum spectroscopy of the fragmentation products have been performed. From these, the total reaction cross section and the branching ratios of the different product states were derived. These kind of studies will be continued at the new electrostatic and Cryogenic Storage Ring (CSR) in Heidelberg. Operated at cryogenic temperatures, the vacuum conditions are improved by several orders of magnitude which enables the storage of heavy molecules in their lowest ro-vibrational quantum state. In this way, gas phase processes can be investigated under conditions similar to those found in interstellar media. A new multicoincidence particle imaging detector was developed. For experiments on dissociative recombination in this harsh environment, the detector has been partly simulated, constructed, built and tested