Regensburg 2016 – wissenschaftliches Programm
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UP: Fachverband Umweltphysik
UP 6: Additional Topics
UP 6.3: Vortrag
Mittwoch, 9. März 2016, 12:30–12:45, H41
Applications of 39Ar-ATTA in the environment: pilot studies for ocean- and ice-research — Stefan Beyersdorfer1, •Florian Ritterbusch1, Arne Kersting1, Emeline Mathouchanh1, Sven Ebser2, Zhongyi Feng2, Helene Hoffmann1, Toste Tanhua3, Werner Aeschbach1, and Markus K. Oberthaler2 — 1Institute of Environmental Physics, Heidelberg University, Germany — 2Kirchhoff-Institute for Physics, Heidelberg University, Germany — 3GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
Atom Trap Trace Analysis (ATTA) is a novel ultra-sensitive detection method for rare noble gas radioisotopes. In Heidelberg, an ATTA setup has been realized for 39Ar (half-life 269 a) which is the only reliable dating isotope for water and ice in the range of 50-1000 a. After the successful demonstration of 39Ar dating for large groundwater samples (1-2 m3 of water) current developments aim at shorter measurement times and smaller sample sizes of 10-25 L of water or 4-10 kg of ice. An argon extraction system for such samples based on vacuum degassing and a Ti-Getter has been developed, achieving argon purities > 98% and recoveries > 95%. The extraction system has been used for the preparation of samples from a pilot study for 39Ar dating of ocean water masses in the oxygen minimum zone of the Eastern Tropical North Atlantic. Moreover, samples have been processed from a pilot study at the Gorner Glacier (Swiss Alps), which uses 39Ar to provide an absolute age for different positions along the flowlines. The developed sample preparation methods are an important ingredient for the wide range of future applications that the advent of 39Ar-ATTA opens up.