Towards an Australian Atom-Trap Trace-Analysis (ATTA) Facility

摘要

Atom-Trap Trace-Analysis (ATTA) is a technique aimed at a measuring the relative (in comparison to the commonisotope) abundance of exceedingly rare noble gas radio-isotopes (Ar-39, Kr-81 and Kr-85), for the purposes of datingwater, ice and other materials that contain trapped gases. These isotopes exist with an extremely low natural abundanceand require measurement capability down to parts in 1017. The noble gas dating protocol is similar to that of radio-carbondating but, the three isotopes together, allow dating of materials in complementary ranges to that possible with the radiocarbontechnique. In a facility jointly created by CSIRO, Griffith and Adelaide Universities, we use laser guidance,cooling and trapping to perform isotopic separation using the isotopic dependence of atomic energy levels. The facility iscurrently undergoing construction but has been shown to be able to produce metastable Ne and Ar, which can then belaser cooled and trapped. When combined with the existing gas separation facility at the CSIRO Waite facility, whichefficiently extracts pure noble gases from that are dissolved in water or ice samples, we should be in a position to startmeasuring the age of real-world samples in the early part of 2020. In addition, to describing the current state ofconstruction, we will also discuss two more efficient approaches for creating metastable atoms that can reduce samplessize and avoid unwanted cross-contamination between samples.