Vicinage effect on secondary-electron emission in the forward direction from amorphous carbon foils induced by swift C2+ ions
Vicinage effect on secondary-electron emission in the forward direction from amorphous carbon foils induced by swift C2+ ions
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快速 C2 离子诱导的非晶碳箔正向二次电子发射的邻近效应
DOI：
10.1209/0295-5075/88/63001
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Y. Maeda
中科院分区：
文献类型：
--
作者：
Y. Takahashi;K. Narumi;A. Chiba;Y. Saitoh;K. Yamada;N. Ishikawa;H. Sugai;Y. Maeda
对于 61-150μg/cm2 的厚箔，首次观察到用 62.5keV/u C2+ 离子轰击的无定形碳箔的正向二次电子产率的邻近效应消失。通过考虑库仑爆炸计算碎片离子的轨迹来确定邻近效应消失的阈值核间距离，以估计引起邻近效应的特征相互作用长度。阈值核间距离远大于能量损失，这与散射电子产生二次电子发射的过程有关。此外，阈值核间距离随着离子速度的增加而增加。该结果意味着散射电子的传输或传输过程对于邻近效应的出现非常重要。
For the first time the disappearance of the vicinage effect on the secondary-electron yield in the forward direction from amorphous carbon foils bombarded with 62.5 keV/u C2+ ions was observed for thick foils of 61–150 μg/cm2. The threshold internuclear distance where the vicinage effect disappears was determined by calculating trajectories of the fragment ions considering the Coulomb explosion in order to estimate the characteristic interaction length that causes the vicinage effect. The threshold internuclear distance is much larger than that for the energy loss, which is related to a production process of scattered electrons leading to the secondary-electron emission. Moreover, the threshold internuclear distance increases as the velocity of the ion increases. This result means that a transport or transmission process of scattered electrons is very important for the appearance of the vicinage effect.