| Summary: | 81 Kr is a cosmogenic isotope with half-life of 229 ka. Its dating range is 20-1300 ka, which covers many applications for polar ice. 81 Kr can provide absolute, radiometric ages and do not rely on continuous stratigraphy. Thus it is complementary to conventional ice dating techniques and is particularly valuable for disturbed ice samples. 81 Kr dating on 200 kg blue ice samples from the Taylor Glacier has been demonstrated in 2014, using the Atom Trap Trace Analysis (ATTA) method. Over the past decade, there has been continuous efforts to reduce the sample size used by the ATTA method so that it can do 81 Kr dating on deep ice cores, especially the stratigraphically disturbed ones. In this talk, I will present some of our works along this journey and report our recent technical breakthrough on the all-optical ATTA method. By using the optical excitation scheme in ATTA, the memory effect is significantly suppressed, allowing us to reduce the sample size to 1 kg. The performance of the new all-optical ATTA dating method has been verified with ice core samples from Taylor glacier.
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