摘要
抑制二次电子倍增效应是提高空间大功率微波器件和粒子加速器等设备性能的重要课题,而使用表面处理降低材料的二次电子发射系数是抑制二次电子倍增的有效手段.为优化寻找抑制效果最好的表面形貌,本文采用蒙特卡罗方法模拟了各种微米量级不同表面形貌的二次电子发射特性,研究占空比、深宽比、结构形状及排列方式等的影响.模拟结果表明,正方形、圆形、三角形凸起和凹陷结构的二次电子发射系数随占空比和深宽比的增大而减小,但存在饱和值;凸起结构的排列方式对二次电子发射系数的影响不大,但是凸起结构形状却对二次电子发射系数的影响较大,其中三角形的抑制效果最佳.对凹陷结构而言,不同形状的抑制效果差别不大;同时,占空比和深宽比相同时,凸起结构较凹陷结构抑制效果更佳.究其原因,核心在于垂直侧壁的"遮挡效应",凹陷结构遮挡效应的大小与"陷阱"垂直高度有关,而凸起结构遮挡效应的大小和凸起部分的斜方向投影大小有关.
Suppression of the secondary electron（SE） multipactor is a key issue for improving the performance of high power microwave devices and particle accelerators. The decrease of the SE emission yield（SEY） by using certain surface morphology is one of the effective methods. To optimize the surface morphology, we simulate the SE emissions of different surface structures by using the Monte Carlo method. The effects of geometric parameters, such as duty ratio of area, depth-to-height ratio, pattern and its arrangement on SEY are investigated. For surface morphology with patterns of square, round and triangle, and for both convex and concave structures, the corresponding values of SEY first decrease and then become steady with the increase of duty ratio of area and depth-to-height ratio. For convex structures, the values of SEY are different for different pattern shapes, in which triangle pattern has the smallest SEY. However, the value of SEY is nearly independent of arrangement of pattern. For concave structures, on the other hand, the value of SEY is scarcely different for different patterns or different arrangements. In general, a convex structure has a better suppression effect than a concave structure if other geometric parameters are identical. The ＂shading effect＂ from side wall of structure is found to be the intrinsic reason of the suppression effect.
作者
胡晶
曹猛
李永东
林舒
夏宁
Hu Jing;Cao Meng;Li Yong-Dong;Lin Shu;Xia Ning(Key Laboratory for Physical Electrons and Devices of the Ministry of Education,Department of Electronic Science and Technology,School of Electronic and Information Engineering,Xi＇an Jiaotong University,Xi＇an 710049,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2018年第17期276-286,共11页
Acta Physica Sinica
基金
国家自然科学基金(批准号:U1537210
11375139)资助的课题~~
关键词
二次电子发射
凹陷结构
凸起结构
微放电敏感区域
secondary electron emission
concave structure
convex structure
multipactor susceptibility zone
