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

稀有气体放射性同位素39Ar对于海洋学、冰冰学和水文地质学的测年应用具有极大的兴趣，因为它是唯一覆盖大约50到1000年重要年龄范围的同位素。原子陷阱痕量分析（ATTA）的全新分析技术首次使81Kr测年成为可能，有可能通过将样本量要求减少100到1000倍，彻底改变39Ar的应用。在之前的一个项目中，我们首次证明了ATTA对自然样品进行39Ar分析是可能的，尽管我们仍然需要通常的吨水。最近，我们使用了针对海水和高山冰的第一个试点项目的样品，证明了39Ar-ATTA （ArTTA）分析大约25升水或10毫升Ar甚至更少的样品是可行的。这一成就为39ar测年的应用提供了全新的视角，提供了迄今为止尚未获得的非常有价值的信息。对这种分析的需求，特别是在示踪海洋学领域，是由我们目前的ArTTA应用合作伙伴的支持信所证实和记录的。这一建议将使我们能够构建世界上第一个针对小样本常规操作的ArTTA仪器。我们的目标是建立一个39Ar测年平台，以满足地下水研究、海洋学和冰川研究等领域的测年需求。为了使示踪剂海洋学有意义的应用，每年至少需要200个样品的能力。这种新的研究工具将使长期寻求的应用成为可能，否则这些应用是不可能实现的。根据之前的研究，我们有一个明确的计划来建立一个完整的ArTTA操作平台：一条新的基于反应气体的样品制备线，可以在几个小时内从小的（< 25升的水或10公斤的冰）环境样品中分离出高达10毫升的纯Ar。这些样品被转移到ArTTA设备，该设备由2个模块组成：光学模块产生适当的激光频率和激光功率，原子模块是使用先前项目原型中实现的原子光学工具检测原子的部分。设备将尽可能采用可靠、高性能的商用部件。该系统将安装在高度受控的容器环境中，提供模块化设置，将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.