Improvements on Atom Trap Trace Analysis of <sup>39</sup>Ar

ORAL

Abstract

The noble gas radioisotope 39Ar (half-life = 268 years) is a natural clock in the environment and nearly ideal for dating water and ice in the age range of 50-1800 years due to its gaseous and inert properties. This extremely rare isotope (isotopic abundances in the environment of 10-17-10-15) can be measured by the laser-based method Atom Trap Trace Analysis (ATTA), which features ultra-high selectivity and sensitivity. However, in the past the use of 39Ar dating in applications such as dating of ocean water and ice cores was hampered by sample size requirement, precision and sample throughput of the 39Ar analysis.

We report on the latest advances of 39Ar analysis using ATTA, including increased 39Ar detection efficiency and a reduced 39Ar background, resulting in a two-fold increase in the upper age limit of 39Ar dating. Moreover, we have developed a 39Ar pre-enrichment system based on mass spectrometric techniques and obtain 39Ar count rates up to 1000 atoms/h, two orders of magnitude higher than in previous efforts. This allows for a considerably higher sample throughput, which is particularly crucial for large scale surveys of global ocean circulations. Thanks to the progress in 39Ar analysis, the full potential of radioargon dating over a wide timescale can now be exploited in groundwater, ocean water and glacier ice.

http://atta.ustc.edu.cn/en-us/events/attaprimer.html

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Presenters

  • yanqing Chu

    • University of Science and Technology of China, Hefei, China

Authors

  • yanqing Chu

    • University of Science and Technology of China, Hefei, China

  • Amin Tong

    • University of Science and Technology of China, Hefei, China

  • Jiqiang Gu

    • University of Science and Technology of China, Hefei, China

  • Xize Dong

    • University of Science and Technology of China
    • University of Science and Technology of China, Hefei, China

  • Shuiming Hu

    • University of Science and Technology of China, Hefei, China

  • Weikang Hu

    • University of Science and Technology of China, Hefei, China

  • Zehua Jia

    • Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China

  • Wei jiang

    • University of Science and Technology of China
    • University of Science and Technology of China, Hefei, China

  • Zheng-Tian Lu

    • University of Science and Technology of China
    • University of Science and Technology of China, Hefei, China

  • Florian Ritterbusch

    • University of Science and Technology of China
    • University of Science and Technology of China, Hefei, China

  • Liangting Sun

    • Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China

  • Zhaofeng Wan

    • University of Science and Technology of China, Hefei, China

  • Guoming Yang

    • University of Science and Technology of China, Hefei, China