ArTTA-10mL: An instrument for 39Ar-dating of small ice and water samples

惰性气体放射性同位素39 Ar在海洋学、冰川学和水文地质学的测年应用中具有很大的意义，因为它是唯一能覆盖50 - 1000年重要年龄范围的同位素。原子阱痕量分析（ATTA）是一种全新的分析技术，它首次使81 Kr测年成为可能，有可能彻底改变39 Ar的应用，将样品量减少100至1000倍。在之前的一个项目中，我们首次证明了ATTA对天然样品进行39 Ar分析是可能的，尽管我们仍然需要通常的水。最近，使用针对海水和高山冰的第一个试点项目的样品，我们已经证明了对约25 L水或10 mL Ar或更少的样品进行39 Ar-ATTA（ArTTA）分析是可行的。这一成就为39 Ar测年的应用提供了全新的视角，提供了迄今为止无法获得的极有价值的信息。对这种分析的需求，特别是在示踪海洋学领域，是明确的，并记录在我们目前的合作伙伴对ArTTA应用的支持信中。该提案将使我们能够构建全球第一台针对小样本常规操作的ArTTA仪器。我们的目标是建立一个39 Ar测年平台，以满足地下水研究，海洋学和冰川研究领域的测年需求。为了能够在示踪海洋学中有意义地应用，每年至少需要200个样本。这一新的研究工具将使长期寻求的应用成为可能，否则是不可能的。基于之前的研究，我们有一个明确的计划，为ArTTA操作建立一个完整的平台：一个新的样品制备线基于反应气体的吸气，可以在几个小时内从小环境样品（< 25 L的水或10 kg的冰）中分离出高达10 mL的纯Ar。这些样品被转移到ArTTA装置，该装置由2个模块组成：光学模块产生适当的激光频率和激光功率，原子模块是使用原子光学工具检测原子的部分。设备将尽可能使用可靠、高性能的商用部件。该系统将安装在高度受控的集装箱环境中，提供模块化设置，未来可以安装在不同的地方。

The noble gas radioisotope 39Ar is of great interest for dating applications in oceanography, glaciology, and hydrogeology, because it is the only isotope to cover the important age range between about 50 and 1000 yr. The fundamentally new analytical technique of Atom Trap Trace Analysis (ATTA), which for the first time has rendered 81Kr dating possible, has the potential to revolutionize the application of 39Ar, by reducing sample size requirements by a factor of 100 to 1000. In a previous project we have for the first time demonstrated that 39Ar analysis of natural samples by ATTA is possible, although we still needed the usual tons of water. Very recently, using samples from first pilot projects targeting ocean water and alpine ice, we have demonstrated that 39Ar-ATTA (ArTTA) analysis on samples of about 25 L of water or 10 mL of Ar or even less is feasible. This achievement enables completely new perspectives for the application of 39Ar-dating, providing highly valuable information so far not accessible. The demand for such analyses, in particular in the field of tracer oceanography, is well established and documented by support letters of our current partners for ArTTA applications. This proposal will enable us to construct the worldwide first ArTTA instruments targeted at routine operation with small samples. We aim at building a 39Ar dating platform that meets the needs for dating in the fields of groundwater research, oceanography and glacier research. In order to enable meaningful applications in tracer oceanography, a capacity of at least 200 samples per year is required. This new instrument for research will enable long-sought applications which otherwise would not be possible. Based on previous research we have a clear plan for setting up a complete platform for ArTTA operation: A new sample preparation line based on gettering of reactive gases enables the separation of up to 10 mL of pure Ar from small (< 25 L of water or 10 kg of ice) environmental samples in a few hours. These samples are transferred to the ArTTA apparatus, which consists of 2 modules: the optics module produces the proper laser frequencies and laser power, the atomic module is the part where the atoms are detected employing the atom optical tools realized in the prototype from the previous project. As far as possible the apparatus will be built from reliable, high-performance commercial parts. The system will be installed in highly controlled container environment offering a modular setup which in the future can be installed at different places.