We present a method for improving detection limits of Atom Trap Trace Analysis for the krypton radioisotopes 85Kr and 81Kr. For the case of 85Kr this work demonstrates that systematic use of isotopically depleted gas for calibration and extended conditioning of the instrument results in a detection limit of 900 85Kr atoms per 11 µl of Kr gas, equivalent to a 85Kr/Kr isotopic abundance of 3 × 10–15. This improvement of roughly two orders of magnitude over previously reported limits will help to expand the reach of radiokrypton dating towards longer age ranges where most of the radioisotopes have decayed. Additionally, the method offers an opportunity to investigate radiokrypton production via spontaneous fission within naturally occurring minerals to understand potential underground production of these isotopes.

中文翻译：

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放射性氪分析的增强检测限

我们提出了一种提高氪放射性同位素 85Kr 和 81Kr 的原子阱痕量分析检测限的方法。对于 85Kr，这项工作表明，系统地使用同位素耗尽气体进行仪器校准和扩展调节导致每 11 µl Kr 气体 900 个 85Kr 原子的检测限，相当于 3 × 的 85Kr/Kr 同位素丰度10-15。与先前报告的限制相比，这种改进大约两个数量级将有助于扩大放射性氪测年的范围，使大多数放射性同位素衰变的年龄范围更长。此外，该方法提供了一个机会，通过天然矿物中的自发裂变来研究放射性氪的产生，以了解这些同位素的潜在地下生产。