减速场分析仪透射率与栅网结构关系分析  

Effect of Grid Geometry on Transmittance of Retarding Field Analyzer:A Simulation Study

作　　者：霍昆 任志杰 孙玄[1] Huo Kun;Ren Zhijie;Sun Xuan(University of Science and Technology of China, Hefei 230026, China)

机构地区：[1]中国科学技术大学,合肥230026

出　　处：《真空科学与技术学报》2019年第3期230-236,共7页Chinese Journal of Vacuum Science and Technology

基　　金：国家重点研发计划(2017YFA0402500)

摘　　要：为对科大全对称串节磁镜(KMAX)装置中等离子体离子能量分布和离子温度进行测量,需要设计一种减速场分析仪,而分析仪测出的数据被认为是复杂的,因为透射率与栅网的结构存在密切关系。结合实际物理环境,通过COMSOL创建三栅网减速场分析仪模型,对比不同能量离子束、不同栅网结构以及不同入射角对透射率的影响。栅网间透镜效应对于低能离子束透射率具有重要影响,而高能离子束透射率趋近于光学透射率,栅网对齐分布具有更高的透射率,相同光学透射率网格中圆形网格透射率更高,光学透射率越高栅网实际透射率也越高。透镜效应对于不同能量离子束的影响不同,栅网网格形状、单栅网光学透射率、栅网分布均对总透射率有影响,针对KMAX装置设计的分析仪有效入射角度范围0°～10°,栅网结构与透射率关系的研究结果对于减速场分析仪设计具有一定的参考意义。The ion-beam transport in triple-grid retarding field analyzer(RFA),installed in the lab-built Mirror with Axisymmetricity,was mathematically modeled and numerically simulated with software COMSOL for design optimization.The influence of the incident-angle/energy of ion beam and grid-structure on the RFA's transmittance was investigated.The simulated results show that the ion-beam properties and grid-structure all have a major impact.To be specific,as the ion beam energy increased,RFA's transmittance increased,approaching to the optical transmittance at a high energy because of significantly weakened inter-grids lens effect;RFA's transmittance depends on the incident angle of ion beam and on the properties of each grid,including the optical transmittance,mesh-shape,mesh-size and mesh-alignment.For example,a grid with circular-mesh has higher transmittance than that with square-mesh.Moreover,the ion incident angle should in 0°~10° range.

关 键 词：减速场分析仪 栅网结构 离子能量分布函数 透射率 

分 类 号：TL656[核科学技术—核技术及应用]