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Q: Fachverband Quantenoptik und Photonik
Q 16: Laser Developments and Applications
Q 16.6: Vortrag
Montag, 11. März 2019, 15:15–15:30, S SR 211 Maschb.
Novel Quantum Physical 39Ar Dating of Alpine Glacier Ice, Ocean- and Lake Water with Small Sample Sizes — •Maximilian Schmidt1,2, Zhongyi Feng2, Lisa Ringena2, Arne Kersting1, Julian Robertz2, Sven Ebser2, Werner Aeschbach1, and Markus K. Oberthaler2 — 1Institute of Environmental Physics Heidelberg — 2Kirchhoff-Institute for Phyics Heidelberg
The cosmogenic radioisotope 39Ar (t1/2 = 269 a) offers the possibility for radiometric dating in a time span of 50 -1000 years and thus is capable of studying dynamics of aquatic and glacial systems of the last millennium. So far its natural isotopic abundance of 39Ar/Ar = 8·10−16 and long lifetime required sample sizes of about 1000L. The utilization of quantum optical techniques widely used in atomic physics solves the problem by reducing sample volume requirements by three orders of magnitude. The problem of the very low isotopic abundance is resolved by resonant multi-photon scattering of 39Ar in an atom trap. This technique named Argon Trap Trace Analysis (ArTTA) is the door opener for new geophysical research fields that were excluded from radio-argon dating so far due to large sample size requirements. Here we present our most recent results covering multi-tracer dating studies with ocean- and lake water and glacier ice using sample sizes of about 10-20 L of water and 5-10 kg of ice respectively corresponding to 0.5-20 mLSTP argon. The significant sample size reduction makes standard sampling techniques like Niskin bottles for aquatic systems and drill core sampling for glacial systems feasible.