Cologne Noble Gas Mass Spectrometry

Complementing the CologneAMS facility for measuring ¹⁰Be, ²⁶Al and ³⁶Cl for terrestrial cosmogenic nuclide studies, our working group hosts a Helix MC Plus (Thermo Scientific) noble gas mass spectrometer dedicated to the measurement of cosmogenic noble gas isotopes.

The system was funded by the German Research Foundation (Project number 259990027) and is geared for state of the art high‐precision and trace analysis of cosmogenic noble gas isotopes in quartz (^21,22Ne), zircon (^78,81Kr) and He‐retentive minerals (³He; e.g. iron‐oxides, pyroxene, olivine). The performance of the system for cosmogenic neon analysis is on par with its international peers (Ritter et al. 2021; see also Fig. 9 of Györe et al. 2021, https://doi.org/10.3390/geosciences11080353). The system is the first installation to perform in-situ cosmogenic krypton measurements on terrestrial material (Dunai at al. 2022).

Samples are heat-extracted utilizing an IR-fiber-laser that is equipped with a software-controlled galvanic scanning head. Sample gases are purified via sequential exposure to two reactive metal getters and a watertrap, and separated using dual-head cryotrap. For ease of operation and reproducibility of results, the use of cooling liquids (e.g. CO₂-slush or liquid N₂) is avoided, while maintaining low backgrounds of relevant interferences. The purification and cryogenic separation of noble gases follows a fully automated sequence developed using LabView (Ritter et al. 2021).

- T.J. Dunai, S.A. Binnie and A. Gerdes 2022 In situ-produced cosmogenic krypton in zircon and its potential for Earth surface applications, Geochronology 4, 65–85, https://doi.org/10.5194/gchron-4-65-2022
- B. Ritter, A. Vogt and T.J. Dunai 2021 Technical Note: Noble gas extraction procedure and performance of the Cologne Helix MC plus multi-collector noble gas mass spectrometer for cosmogenic neon isotope analysis, Geochronology 3, 421–431, https://doi.org/10.5194/gchron-3-421-2021