講演情報
[9a-N324-2]Influence of surface pre-treatment on the nano-tendril bundles (NTB) and micropillars obtained via contaminated He ion irradiation
〇(P)Fabien Sanchez1, Shin Kajita2, Hirohiko Tanaka3, Ryoji Mano4, Shoma Hirata4, Hayashi Koki4, Ryo Yasuhara1,5, Quan Shi2, Noriyasu Ohno4, Hiyori Uehara1,5 (1.National Institute for Fusion Science, Toki 509-5292, Japan, 2.Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8561, Japan, 3.Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, 464-8603, Aichi, Japan, 4.Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan, 5.The Graduate University for Advanced Studies, SOKENDAI, 322-6 Oroshi-cho, Toki, Gifu 509-5202, Japan)
キーワード：
Helium plasma irradiation、Nano-tendril bundles (NTB)、Nanopatterning
In fusion reactors, helium (He) ions will irradiate the first wall. These energetic ions will bombard the plasma-facing components located in the reactor's highest heat-flux region (divertor) which is made of tungsten (W). In addition to He, the divertor environment will likely include sputtered species originating from tokamak walls and plasma-seeded gases. These irradiation conditions have revealed the formation of nano-tendril bundles (NTB) [3] and micrometric pillars. The formation of these structures enhance the material field emission properties and increase the arcing probability, which is a detrimental for fusion reactors. However, the formation mechanisms of those structures are still not understood yet. Hence, the understanding of the mechanisms leading to NTB and micropillars is essential for predicting material behavior under fusion-relevant conditions. In this work, W substrates were annealed or unpolished prior to the irradiation. NTB and micropillar structures were produced with on those pre-treated surfaces using He plasma containing neon (Ne) or argon (Ar). For both structures, the structure sizes and coverage were drastically affected by the surface pre-treatment, demonstrating the importance of the initial surface state in the final NTB formation. This work will introduce those new findings and propose micropillars and NTB formation mechanisms.