Comparative investigations of stainless steel and molybdenum first mirrors cleaning using radio frequency plasma
Comparative investigations of stainless steel and molybdenum first mirrors cleaning using radio frequency plasma
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DOI：
10.1016/j.fusengdes.2016.08.025
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发表时间：
2016-11
影响因子：
1.7
通讯作者：
J. Peng;L. Chen;R. Yan;Junling Chen;Dahuan Zhu;R. Ding;Q. Wang;Z. M. Zhang
中科院分区：
文献类型：
--
作者：
J. Peng;L. Chen;R. Yan;Junling Chen;Dahuan Zhu;R. Ding;Q. Wang;Z. M. Zhang
ITER中用于光学诊断的第一反射镜（FM）面临着从面向等离子体的部件上腐蚀下来的杂质再沉积的严重威胁。采用射频等离子体清洗方法去除不锈钢（SS）和多晶钼（Mo）薄膜上的沉积物，以恢复其高反射率。经过清洗工艺，沉积在SS FM上的非晶碳膜被成功去除。总反射率恢复到95%以上，漫反射率低于5%。与初始值相比，清洁后的SS反射镜的粗糙度几乎没有变化。对于Mo镜，在可见光波长下的总反射率恢复到85%，而漫反射率由于更高的粗糙度而增加到17%。对钼镜表面的XPS分析表明，钼的碳化物形成于膜基界面处，是造成清洗效果与不锈钢镜不同的原因之一。
First mirrors (FMs) used in optical diagnostics in ITER are confronted with a serious threat of the re-deposition of impurities eroded from plasma facing components. The radio frequency plasma cleaning method was applied to remove deposits on stainless steel (SS) and polycrystalline molybdenum (Mo) FMs for recovering their high reflectivity. After cleaning process, the amorphous carbon film deposited on SS FM was successfully removed. The total reflectivity was recovered up to 95% and the diffuse reflectivity was lower than 5%. The roughness of the cleaned SS mirror was almost not changed compared with the initial value. For Mo mirror, the total reflectivity was restored to 85% in the visible wavelength, while the diffuse reflectivity was increased to 17% due to higher roughness. The XPS analysis on Mo mirror surface showed that Mo carbide was formed at the interface between the substrate and film, which made a contribution to the difference of cleaning results from SS mirror.