Towards large-scale application of 39Ar in ocean circulation studies
ATTA is a laser based atom counting method capable of detecting noble gas isotopes with extremely low abundance (10-16 – 10-10). A laser trap is used to capture and detect atoms of the interested isotope. This method is highly selective and free of interference of any isobar or molecular species. Fig. 1 shows the performance of the 39Ar dating apparatus. New development is underway to increase the counting rate, a major limitation of the current instrument. This effort would improve the dating precision to 5% and the capacity to 300 samples per year.
Figure 1 39Ar dating uncertainty as a function of sample age. (Typical sample size is 1 mL STP of argon gas which can be extracted from 2-4 kg of seawater.).