First direct comparative test of single crystal rhodium and molybdenum mirrors for ITER diagnostics
First direct comparative test of single crystal rhodium and molybdenum mirrors for ITER diagnostics
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DOI：
10.1016/j.fusengdes.2017.03.053
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发表时间：
2017-11
期刊：
影响因子：
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通讯作者：
A. Litnovsky;Y. Krasikov;M. Rasinski;A. Kreter;C. Linsmeier;P. Mertens;B. Unterberg;U. Breuer;T. Wegener
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文献类型：
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作者：
A. Litnovsky;Y. Krasikov;M. Rasinski;A. Kreter;C. Linsmeier;P. Mertens;B. Unterberg;U. Breuer;T. Wegener
ITER的所有光学和激光诊断都将使用镜子来观察等离子体辐射。在ITER环境中，反射镜可能会被等离子体杂质污染，从而影响相应诊断的性能。提出了一种基于离子溅射污染物和受影响的镜面材料的原位镜面清洗方法。先前的研究表明，在溅射条件下，单晶（SC）钼（Mo）优于多晶概念。最近，第一个单晶铑（Rh）镜已经可用，并且已经在Forschungszentrum j<s:1> lich开始测试。在线性等离子体装置PSI 2中，SC Rh和SC Mo反射镜在相同条件下暴露于稳态氦等离子体中。撞击离子的能量为~ 100 eV，符合ITER原位学习系统的预期条件。在曝光过程中，由于溅射，钼镜损失了420-500 nm。铑镜损失约1 μm。暴露在ITER中相当于50-100次清洗循环。然而，铑反射镜保留了它们的镜面反射率，在250 nm处显示出小于7%的最大退化。钼反射镜的镜面反射率适度降低了12-25%。结果为单晶在ITER诊断中的应用开辟了新的前景。
All optical and laser diagnostics in ITER will use mirrors to observe the plasma radiation. In the ITER environment, mirrors may become contaminated with plasma impurities hampering the performance of corresponding diagnostics. Anin-situmirror cleaning is proposed, which relies on ion sputtering of the contaminants and the affected mirror material. Previous research demonstrated the advantages of single crystal (SC) molybdenum (Mo) under sputtering conditions over polycrystalline concepts. Recently, the first single crystal rhodium (Rh) mirrors became available and tests have been started at the Forschungszentrum Jülich.In a direct test, SC Rh and SC Mo mirrors were exposed under identical conditions in steady-state helium plasmas in the linear plasma device PSI 2. The energy of impinging ions was ∼100 eV matching conditions expected in thein-situcleaning system in ITER. During exposure, molybdenum mirrors lost 420–500 nm due to sputtering. Rhodium mirrors lost about 1 μm. Exposure corresponded to 50–100 cleaning cycles in ITER. Nevertheless, rhodium mirrors have preserved their specular reflectivity, showing the maximum degradation of less than 7% at 250 nm. Molybdenum mirrors demonstrated a moderate decrease of specular reflectivity of 12–25%. Results open new perspectives for the use of single crystals in ITER diagnostics.