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Q: Fachverband Quantenoptik und Photonik
Q 44: Laser Development and Applications
Q 44.7: Vortrag
Donnerstag, 12. März 2020, 12:30–12:45, f435
Argon Trap Trace Analysis: Radiometric dating of environmental samples with applied quantum technology — •Lisa Ringena1, Julian Robertz1, Maximilian Schmidt1,2, Niccolo Rigi-Luperti1, Florian Sandel1, Jeremias Gutekunst1, Arne Kersting2, Yannis Arck2, David Wachs2, Annabelle Kaiser2, Werner Aeschbach2, and Markus Oberthaler1 — 1Kirchhoff Institute for Physics, Heidelberg, Germany — 2Institute for Environmental Physics, Heidelberg, Germany
The measurement of the radioisotope 39Ar opens a unique path towards dating of environmental samples from the last millennium, due to 269 years half-life, chemical inertness and well-known atmospheric concentration. However, its low relative abundance of 39Ar/Ar ∼ 8*10−16 hinders the use of standard analysis schemes. Argon Trap Trace Analysis (ArTTA) enables detection by employing the isotopic shift in the resonance frequency of an optical dipole transition. The trapping of 39Ar inside a magneto-optical trap grants perfect selectivity due to a multitude of resonant scattering processes. In the trap, single 39Ar atoms are captured and counted, while the huge background of abundant isotopes remains unaffected. During the last years, the apparatus was successfully used to study groundwater, ocean, ice and lake water samples. A second machine for higher throughput is currently set up, the status of which will be presented. In respect of the original ArTTA dating apparatus, the state of the art regarding sample size limits and measurement uncertainty will be discussed.