Ruprecht-Karls-Universität Heidelberg
Grundwasser und Paläoklima - Labor

Noble Gas Lab - Technical Details

 

Established in the years 2004-2006, our lab is the most modern of only a handful of laboratories worldwide that can analyse all stable noble gases dissolved in water samples. It builds on the experience of two other leading laboratories, namely at the L-DEO, Columbia University, New York (Ludin et al., 1997) and at ETH Zurich (Beyerle et al., 2000).

Routine procedures for the analysis of major noble gas isotopes from ~ 20 ml water samples as well as ~ 1 cm3 gas samples are now established. Procedures for the analysis of much smaller (~ 1 µl) water samples from fluid inclusions are currently being developed.

Details on the system are described in a recent PhD-thesis (Friedrich, 2007) and will be published elsewhere soon.

 

Technical Description: 

GV 5400He Noble Gas Mass Spectrometer

  • Static vacuum mass spectrometer suitable for the measurement of He, Ne, Ar, Kr, Xe.

  • 90° magnetic sector analyser, Nier type ion source, Faraday and Muliplier detectors.

  • High resolution (~ 600) and sensitivity (> 5x10-4 A/Torr for Ar), low background.

  • Installed in 2004

Fully automated, custom-built preparation line

  • Fully automated and computer controlled with ~ 30 pneumatic valves.

  • Cryogenic purification system operated between 8 and 300 K.

  • Ultra-high vacuum system (< 10-8 mbar).

  • Inlet systems for water, gas, and rock (fluid inclusion) samples.

Calibration and performance

  • Absolute calibration is performed against aliquots of an air standard.

  • Precision (reproducibility) for concentrations is < 1 % except for Xe (< 1.5 %).

  • Precision for major isotope ratios is usually < 0.5 % except for 3He/4He (< 2 %).

  • Standard water analyses take about 3 hours, blanks and calibrations are run overnight.

 

References cited:

Ludin, A., Weppernig, R., Boenisch, G., and Schlosser, P., 1997. Mass spectrometric measurement of helium isotopes and tritium. Lamont-Doherty Earth Observatory, Technical Report.

Beyerle, U., Aeschbach-Hertig, W., Imboden, D. M., Baur, H., Graf, T., and Kipfer, R., 2000. A mass spectrometric system for the analysis of noble gases and tritium from water samples. Env. Sci. Technol. 34, 2042-2050.

Friedrich, R., 2007. Grundwassercharakterisierung mit Umwelttracern: Erkundung des Grundwassers der Odenwald-Region sowie Implementierung eines neuen Edelgas-Massenspektrometersystems. Dissertation, Universität Heidelberg, 271 pp.

 

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