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Abstract

Collisions between ions and neutrals are decisive for the gas-phase synthesis of
complex molecules in the interstellar medium. In order to model the astrochemical
network, rate coefficients of existing reactions are required. However, these
coefficients were barely measured under astrophysical conditions. The Cryogenic
Storage Ring (CSR), housed by the Max Planck Institute for Nuclear Physics, is
capable of merging stored and cooled ions with a neutral beam. This results in
extremely low collision energies in a low pressure environment. In order to verify
the collision temperatures, collisions between H⁺₃
and C were simulated, a crucial
reaction for organic astrochemisty. The particle tracking program G4beamline
was used to simulate the stored ion beam. The neutral beam was calculated by
python in a ballistics approach. The influence of the earth's magnetic field was
evaluated by recording the magnetic field with a fluxgate magnetometer at over
400 measuring points. The compensation of the earth's magnetic field by electromagnetic
coils was simulated by the _nite element program Opera-3D. Thus,
the magnetic field inside the CSR could be reduced to 1/10 of its former power,
enabling collision temperatures down to 64 K.