Development of a multiple continuous-mode gas extraction and purification system from rocks and minerals

为了研制一套能在实验过程中不受二次污染地从岩石和矿物中脱除稀有气体和挥发性元素的气体提取和净化系统，我们对电阻加热法、激光烧蚀法和破碎法等各种脱气方法进行了比较，并尝试将它们联合收割机结合起来。除气不仅发生在Ta炉本身，而且由于加热而发生在附近区域。因此，很难获得很低的空白水平。我们研究了使用线圈加热器的加热方法，该加热器可以在几V和10 A左右的条件下提供高达约2，000 ℃的温度。由于只有线圈加热器达到高温，因此可以获得非常低的空白水平。激光烧蚀法可以加热空白水平较低的样品，与Ta电阻加热法相比，其加热空白水平低两个数量级。问题是，由于在这种情况下脱气的气体量非常低，可用的样品有限。我们开发了几种破碎设备，并检查了破碎效率。我们开发了一种破碎设备，其破碎效率超过90%。我们还计划将该系统安装在钽电阻加热炉的顶部，并在不直接暴露于大气的情况下转移粉碎的样品。通过将该系统与激光烧蚀系统相结合，我们已经展示了多连续模式气体提取和净化系统的可能性。

To develop a gas extraction and purification and purification system which enables us to degas noble gases and volatile elements from rocks and minerals without any secondary contamination during the experimental procedures, we have performed to check each degassing method suc has resistance-heating, laser-ablation and crushing methods and tried to combine them.Concerning the Ta resitance-heating method, degassing occurs not only from the Ta furnace itself but also from the nearby areas due to heating. Hence it is not easy to get very low blank level. We examined the heating method by using coil-heater, which could give a temperature up to about 2,000℃ with the condition of a few V and around 10 A. Since only the coil-heater reaches a high temperature, it is possible to get very low blank level. The problem remains, however, that no appropriate way has been found concerning the support and exchange of samples and has not been used routinely.Laser-ablation method could heat samples with lower blank level with the two orders of magnitude compared with those by using the Ta resistance heating method. It is a problem that available sample is limited due to the very low amount of gases degassed in this case. We have developed several kinds of crushing apparatuses and examine the efficiency of crushing. We have developed a crushing apparatus which has the crushing efficiency of more than 90%. We have further planned to attach such system to the top of the Ta-resistance heating furnace and transfer crushed samples with no direct exposition to the atmosphere. By combining this system with the laser-ablation system we have shown a possibility of multiple continuous-mode gas extraction and purification system.