Plasma cleaning of ITER First Mirrors in magnetic field
Plasma cleaning of ITER First Mirrors in magnetic field
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DOI：
10.1016/j.jnucmat.2014.11.087
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发表时间：
2014-11
影响因子：
3.1
通讯作者：
L. Moser;R. Steiner;F. Leipold;R. Reichle;L. Marot;E. Meyer
中科院分区：
文献类型：
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作者：
L. Moser;R. Steiner;F. Leipold;R. Reichle;L. Marot;E. Meyer
为了避免ITER光学诊断系统的反射率损失，预计将对金属第一镜进行等离子体溅射，以去除来自主壁的沉积物（主要是铍和钨）。因此，等离子体清洗必须在大镜子（尺寸高达200 × 300 mm）上进行，并在强磁场（几特斯拉）的影响下进行。本文介绍了用等离子体清洗沉积在钼反射镜上的铝和氧化铝（用作铍代用品）的结果。使用射频（13.56 MHz）氩等离子体，去除260 nm的混合铝/铝氧化物膜上沉积的磁控溅射镜（98 mm直径）进行了演示。在0.35 T的磁场中，对于场线和镜面之间的各种角度，从测试镜（25 mm直径）上除去50 nm的纯氧化铝。通过进行反射率测量、扫描电子显微镜和X射线光电子能谱来评估清洁效率。
To avoid reflectivity losses in ITER’s optical diagnostic systems, plasma sputtering of metallic First Mirrors is foreseen in order to remove deposits coming from the main wall (mainly beryllium and tungsten). Therefore plasma cleaning has to work on large mirrors (up to a size of 200 × 300 mm) and under the influence of strong magnetic fields (several Tesla). This work presents the results of plasma cleaning of aluminium and aluminium oxide (used as beryllium proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of pure aluminium oxide were removed from test mirrors (25 mm diameter) in a magnetic field of 0.35 T for various angles between the field lines and the mirrors surfaces. The cleaning efficiency was evaluated by performing reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.