Hannover 2016 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 6: Posters II
MS 6.3: Poster
Mittwoch, 2. März 2016, 16:30–19:00, Empore Lichthof
The Heidelberg ATTA setup for 39Ar dating — •Zhongyi Feng1, Sven Ebser1, Anika Frölian1, Maurus Hans1, Lisa Ringena1, Florian Ritterbusch1,2, Werner Aeschbach2, and Markus K. Oberthaler1 — 1Kirchhoff-Institute for Physics, Heidelberg, Germany — 2Institute of Environmental Physics, Heidelberg, Germany
The half-life of 39Ar covers a dating range from 50 to 1000 years before present and is ideal for ocean water and ice samples, but a challenge arises due to the low abundance 39Ar/Ar = 8.23 · 10−16 and the small probe volumes in the order of few liters. Atom Trap Trace Analysis (ATTA) is an ultra-sensitive counting method based on the high selectivity of many photon scattering processes in a Magneto-Optical Trap (MOT) to distinguish the rare isotope from the abundant ones. With this poster we will give a summary of the current status of the experiment and the prospects for dating water samples on a routine basis. We will specifically discuss the possible improvement of the metastable argon source performance utilizing optical pumping inferred from spectroscopic results in a cell. An improved laser setup allowing robust and reliable measurements over many hours as well as alternative cooling schemes will be presented. The smallest possible sample size is currently limited due to a contamination with 39Ar enriched samples. We will present the results of our detailed studies and will discuss measurement strategies which make the dating of water samples in the order of 10 liter possible.