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

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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.