Study on Clarification of Large-Area EB Irradiation Phenomenon by Electron Track Analysis
Study on Clarification of Large-Area EB Irradiation Phenomenon by Electron Track Analysis
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DOI：
10.4028/www.scientific.net/kem.749.118
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发表时间：
2017-08
期刊：
影响因子：
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通讯作者：
Y. Kimura;T. Shinonaga;A. Okada
中科院分区：
文献类型：
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作者：
Y. Kimura;T. Shinonaga;A. Okada
在大面积电子束（EB）照射方法中，可以获得均匀的高能量密度而无需聚焦束。大面积电子束可用于瞬间熔化和蒸发金属表面。阐明了大面积电子束辐照金属模具钢、陶瓷和硬质合金的高效表面光整是可能的。此外，大面积电子束辐照后，凸形尖端往往变圆，尖端材料去除明显。这种现象可能是由于热积累和电子集中在尖端。然而，在大面积EB照射过程中，工件表面附近的电子行为尚未得到澄清。在这项研究中，电子径迹分析进行，以澄清电子行为在大面积EB照射。首先建立了大面积电子束辐照装置的分析模型。在此基础上，通过实验测量了不同能量密度下工件表面的电子束直径，以验证分析模型的准确性。电子束直径的计算结果与实验结果吻合较好。此外，通过计算电子径迹分析得到的表面能量密度分布，阐明了凸形尖端的电子集中现象。分析结果表明，在凸形情况下，能量密度从边缘到尖端逐渐增大，而在平面情况下，能量密度基本不变。实验结果还表明，去除厚度随着相对渗透率的增加而增加。这些结果与能量密度分布的趋势相似。因此，可以通过电子径迹分析来模拟针尖上的电子浓度。
In large-area electron beam (EB) irradiation method, uniformly high energy density can be obtained without focusing the beam. Large-area EB can be used for melting and evaporating metal surface instantly. It was clarified that high efficient surface finishing of metal mold steels, ceramics and cemented carbides was possible by the large-area EB irradiation. Furthermore, the tip of convex shape was often rounded after large-area EB irradiation with remarkable material removal at the tip. This phenomenon is probably caused due to the heat accumulation and electrons concentration at the tip. However, electrons behavior near the workpiece surface during large-area EB irradiation has not yet been clarified. In this study, electron track analysis was conducted in order to clarify electrons behavior during large-area EB irradiation. At first, analytical model of the large-area EB irradiation apparatus was built. Then, the EB diameter on the workpiece surface was experimentally measured with different energy density in order to evaluate the accuracy of our analytical model. The calculated results of EB diameter were in good agreement with the experimental ones. In addition, the electrons concentration phenomenon at the tip of convex shape was clarified by calculating energy density distribution on the surface obtained with electron track analysis. The analytical results indicated that the energy density increased from edge to tip of convex shape, while the energy density was constant in the case of planar shape. Experimented results also showed that removal thickness increases with high relative permeability. These results were similar tendency to the energy density distribution. Therefore, electrons concentration on the tip could be simulated by the electron track analysis.