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MO: Fachverband Molekülphysik
MO 24: Poster: Experimental Techniques
MO 24.6: Poster
Thursday, March 14, 2024, 17:00–19:00, Tent C
Characterization of a simple supersonic expansion source for small molecular ions — •Lukas Berger1, Aigars Znotins1, Florian Grussie1, Damian Müll1, Felix Nüsslein1, Arnaud Dochain2, Joffrey Fréreux2, Xavier Urbain2, and Holger Kreckel1 — 1Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — 2Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, B-1248 Belgium
The Cryogenic Storage Ring (CSR) at the Max Planck Institute for Nuclear Physics in Heidelberg is an electrostatic storage facility with a circumference of approx. 35 m that can be cooled to cryogenic temperatures (∼4 K) by a closed-cycle liquid helium unit. The blackbody radiation field is strongly reduced compared to room-temperature experiments, and small infrared-active molecular ions will cool to their lowest rotational states within minutes in this environment, allowing for experiments with ions in defined quantum states. However, some astrophysically relevant molecular ions do not cool on accessible timescales, owing to the lack of a permanent dipole moment. To address this issue, we have developed a simple supersonic expansion ion source, based on a commercial pulsed valve and static discharge voltages. We have characterized the source performance with N2O+ ions, conducting experiments at the STARGATE setup at UCLouvain (Louvain-la-Neuve, Belgium), which resulted in internal temperatures between 40 K and 200 K. The ion source was then integrated into the ion source platform of the CSR to deliver cold ions for merged beams experiments. The design and performance will be presented.
Keywords: Ion Source; Supersonic Expansion; Cold Ions; Spectroscopy; Rotational Temperature