In-situ measurement of dynamic hydrogen isotope retention under plasma exposure by using ion beam analysis

控制等离子体面组件（PFC）中的氢同位素保留对建立稳态运行至关重要。了解PFC中氢同位素保留的动态行为，对化学溅射加注时间的优化和通量依赖性等具有重要意义。然而，这些现象尚未被理解，主要是由于缺乏适当的等离子体暴露下的等离子体表面分析。在本研究中，我们利用PS-DIBA （plasma Surface Dynamics with Ion Beam Analysis，等离子体表面动力学与离子束分析）装置研究了等离子体暴露下和暴露后石墨中的氘保留，从而使氘保留的原位离子束分析成为可能。我们清楚地观察到氘等离子体暴露在石墨材料中的动态保留，并分析了动态保留的氘粒子的释放时间随氘离子通量的变化。我们还研究了氘和氢之间氢同位素交换的动力学行为。

Control of hydrogen isotope retention in plasma-facing components (PFC) is essential to establish steady-state operation. Understanding of dynamic behavior of hydrogen isotope retention in PFC is quite important related to optimization of the timing of fueling and flux dependence of chemical sputtering, and so on. However, these phenomena have not been understood yet, primarily due to the lack of proper plasma-surface analyses under plasma exposure. In this study, we have investigated deuterium retention in graphite under and after plasma exposure by using a device of PS-DIBA (Plasma Surface Dynamics with Ion Beam Analysis), which makes it possible to carry out in-situ ion beam analysis of deuterium retention. We have clearly observed the dynamics retention in graphite material under deuterium plasma exposure, and analyzed the release time of dynamically retained deuterium particles depending on the deuterium ion flux. We also investigated dynamic behavior of hydrogen isotope exchange between deuterium and hydrogen species.