Saturation of deuterium retention in self-damaged tungsten exposed to high-flux plasmas
Saturation of deuterium retention in self-damaged tungsten exposed to high-flux plasmas
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DOI：
10.1088/0029-5515/52/2/023008
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发表时间：
2012-02
期刊：
影响因子：
3.3
通讯作者：
M. Hoen;B. Tyburska-Pueschel;K. Ertl;M. Mayer;J. Rapp;A. Kleyn;P. Zeijlmans van Emmichoven
中科院分区：
文献类型：
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作者：
M. Hoen;B. Tyburska-Pueschel;K. Ertl;M. Mayer;J. Rapp;A. Kleyn;P. Zeijlmans van Emmichoven
用12.3 MeV的W4+离子轰击多晶、退火的钨靶，造成不同程度的损伤。用高通量等离子体在表面温度低于525K的Pilot-PSI(>；1024m−2 S−1)中注入了氘，用核反应分析和热脱附谱研究了氚的保留。我们发现，在W~(4+)注量约为3×10~(17)m·−~2的情况下，氚的存留率得到了很大的提高，并且达到饱和。损伤区域的最大氚浓度为1.4at.%。这与在低得多的通量下进行的其他实验是一致的。因此，我们得出的结论是，实验中使用的高通量不影响饱和行为和最大保留率。提出了一个简单的几何模型，该模型假定饱和只起源于钨的辐照，并用重叠的饱和体积来解释它。每入射MeV离子的饱和体积为3×10~4Nm~3。从我们的结果，我们能够得到一个职位空缺的平均占有量的近似值。
Polycrystalline, annealed tungsten targets were bombarded with 12.3 MeV W4+ ions to various damage levels. Deuterium was implanted by high-flux plasmas in Pilot-PSI (>1024 m−2 s−1) at a surface temperature below 525 K. Deuterium retention has been studied by nuclear reaction analysis and by thermal desorption spectroscopy. We found that deuterium retention is strongly enhanced by the tungsten bombardment and that saturation occurs at a W4+ fluence of about 3 × 1017 m−2. The maximum deuterium concentration in the damaged region was measured to be 1.4 at.%. This is in accordance with other experiments that were carried out at much lower fluxes. We therefore conclude that the saturation behaviour and the maximum retention are not affected by the high fluxes used in our experiments. A simple geometric model is presented that assumes that the saturation solely originates in the tungsten irradiation and that explains it in terms of overlapping saturated volumes. The saturated volume per incident MeV ion amounts to 3 × 104 nm3. From our results, we are able to obtain an approximate value for the average occupation number of the vacancies.