Heidelberg 2015 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 7: Ion Storage Rings

MS 7.4: Talk

Wednesday, March 25, 2015, 11:45–12:00, PH/HS2

Neutral-atom molecular-ion merged beams experiments at the cryogenic storage ring — •Aodh O Connor, Manfred Grieser, Florian Grussie, and Holger Kreckel — Max-Planck-Institut für Kernphysik, Heidelberg

Gas phase interstellar chemistry is dominated by reactions between neutrals and ions. Thus far, there remain large uncertainties on many reaction rate coefficients, which determine formation pathways. Experimental determination of ion-neutral reaction rates relevant to cosmic chemistry have been inhibited by technical challenges. The greatest obstructions are: generation of a well-defined, pure, ground-term neutral beam, and preparation of molecular ion beams with sufficiently low internal energies. To address these challenges, we have developed a beamline capable of producing atomic beams of hydrogen, deuterium, carbon and oxygen. The neutrals are created by photodetachment from a parent anionic beam using a direct diode laser. The neutral beams are coupled to the Cryogenic Storage Ring (CSR) at the Max Planck Institute for Nuclear Physics. They are merged with a cold, stored molecular ion beam in one of the straight sections of the CSR. The co-propagating beams can be matched in velocity, allowing center-of-mass collisional energies as low as a few meV. Measurement of beam fluxes, velocities, and overlap length will permit absolute determination of the reaction thermal rate coefficients.