Single-crystal and polycrystalline diamond erosion studies in Pilot-PSI
Single-crystal and polycrystalline diamond erosion studies in Pilot-PSI
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Pilot-PSI 中的单晶和多晶金刚石侵蚀研究
DOI：
10.1016/j.jnucmat.2017.12.028
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发表时间：
2018
影响因子：
3.1
通讯作者：
G. Cartry
中科院分区：
文献类型：
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作者：
D. Kogut;D. Aussems;N. Ning;K. Bystrov;A. Gicquel;J. Achard;O. Brinza;Y. Addab;C. Martin;C. Pardanaud;S. Khrapak;G. Cartry
金刚石是一种很有前途的候选人，提高负离子表面生产的离子源中的中性注入聚变反应堆，因此，它对氢等离子体的反应性的评价是非常重要的。单晶和多晶金刚石样品暴露在Pilot-PSI中，D+通量为（4 <$7）·1024 m −2s− 1，在不同的表面温度下每个氘的冲击能量为7-9 eV;在这种条件下，物理溅射可以忽略不计，但化学溅射很重要。在800 °C下，使用预先沉积在单晶上的保护性铂掩模（5 × 10 × 2 μm），然后使用透射电子显微镜（TEM）进行死后分析，精确测量了800 °C下的净化学溅射产额Y = 9.7·10−3at/ion。利用拉曼光谱和X射线光电子能谱（XPS）分析了金刚石表面的结构特征。用CHA-X带发射光谱原位测定了几种表面温度下的总化学溅射产额。在400 °C到1200 °C之间，烧蚀产额与温度呈钟形关系，在900 °C时达到最大产额为1.5·10−2at/ion。金刚石的产率相对较高（0.5-1.5）·10−2at/ion，与石墨相当。XPS分析表明金刚石表面在1 nm深度内发生非晶化，与分子动力学（MD）模拟结果吻合良好。利用分子动力学方法研究了不同温度下氢冲击[100]金刚石表面的侵蚀能量阈值。
Diamond is a promising candidate for enhancing the negative-ion surface production in the ion sources for neutral injection in fusion reactors; hence evaluation of its reactivity towards hydrogen plasma is of high importance. Single crystal and polycrystalline diamond samples were exposed in Pilot-PSI with the D+flux of (4‒7)·1024m−2s−1and the impact energy of 7–9 eV per deuteron at different surface temperatures; under such conditions physical sputtering is negligible, however chemical sputtering is important. Net chemical sputtering yieldY= 9.7·10−3at/ion at 800 °C was precisely measuredex-situusing a protective platinum mask (5 × 10 × 2 μm) deposited beforehand on a single crystal followed by thepost-mortemanalysis using Transmission Electron Microscopy (TEM). The structural properties of the exposed diamond surface were analyzed by Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS). Gross chemical sputtering yields were determinedin-situby means of optical emission spectroscopy of the molecular CH A-X band for several surface temperatures. A bell-shaped dependence of the erosion yield versus temperature between 400 °C and 1200 °C was observed, with a maximum yield of ∼1.5·10−2at/ion attained at 900 °C. The yields obtained for diamond are relatively high (0.5–1.5)·10−2at/ion, comparable with those of graphite. XPS analysis shows amorphization of diamond surface within 1 nm depth, in a good agreement with molecular dynamics (MD) simulation. MD was also applied to study the hydrogen impact energy threshold for erosion of [100] diamond surface at different temperatures.