高功率密度微焦斑X射线源聚焦系统的设计  

Design of a high power density micro-focus spot X-ray source focusing system

作　　者：王丽娟 刘俊标[1,2] 赵伟霞 李文萍[3] 韩立[1,2] WANG Li-juan;LIU Jun-biao;ZHAO Wei-xia;LI Wen-ping;HAN Li(Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049;Beihang University, Beijing 100083)

机构地区：[1]中国科学院电工研究所,北京100190 [2]中国科学院大学,北京100049 [3]北京航空航天大学,北京100083

出　　处：《电子显微学报》2019年第2期112-117,共6页Journal of Chinese Electron Microscopy Society

基　　金：国家重大科学仪器设备开发专项资助项目(No.2017YFF0107202);中国科学院关键技术研发团队资助项目(No.GJJSTD20170005);中国科学院关键技术团队"微纳加工技术及装备研究团队"项目(No.GJJSTD2017004)

摘　　要：X射线源是X射线显微成像系统的核心部件,其功率密度和焦斑大小与聚焦系统密切相关。本文对高功率密度微焦斑X射线源的聚焦系统进行了优化设计,包括透镜结构设计、多透镜工作模式的选择、透镜间距优化等。本文设计了小球差系数的物镜;提出了由聚光镜、辅助聚光镜和物镜组成的多透镜聚焦系统,以实现系统较大的缩放比率和束流较高的传递效率;优化了透镜间距,以保证在满足系统缩放比率的前提下减小聚光镜的安匝数。最后,运用MEBS公司专业电子束计算软件,计算仿真了160 k V的加速电压下聚焦系统中透镜的场分布、电子的运动轨迹、像差、束斑分布等电子光学参量,最终得到束流为80μA,束斑为0. 9μm,功率密度优于1 W/μm^2的微束斑电子束。本文设计的聚焦系统为高功率密度微焦斑X射线源的设计和研制提供了依据。X-ray source is the core component of X-ray microscopic imaging system. Its power density and focal spot size are related to the focusing system closely. In this paper, the focusing system of high power density micro-focus X-ray source is optimized, including lens structure design, multi-lens working mode selection, lens spacing optimization and so on. An objective lens with small spherical aberration coefficient is designed. A multi-lens focusing system consisting of a condensing lens, an auxiliary condensing lens and an objective lens is proposed to achieve a large scaling ratio and a high beam transfer efficiency. The lens spacing is optimized to ensure reducing the excitation of the concentrating lens while satisfying the system scaling ratio. Finally, the electron optical parameters of the focusing system, such as the field distribution, electron trajectory, aberration, beam spot distribution and so on, are calculated and simulated by munro’s professional electron beam calculation software, under the accelerating voltage of 160kV. A microbeam spot electron beam with a beam current of 80 μA, a beam spot of 0.9 μm, and a power density better than 1 W/μm2 was obtained. The focusing system designed in this paper provides a basis for the design and development of high power density micro-focus X-ray source.

关 键 词：高功率密度 电子光学 聚焦系统 磁透镜 电子束 

分 类 号：TN144[电子电信—物理电子学] TH878[机械工程—仪器科学与技术]