100 keV直流光阴极电子枪接入真空电极后的电场仿真  

Electric Field Simulation of 100keV DC Photocathode Electron Gun Connected to High Voltage by Feedthrough

作　　者：李梦超 王瑄[3] 刘巧 袁寿财[1] 荣垂才[1] 陈维[1,2] 黄俊 王兴权[1,2] 卢秀圆 LI Mengchao;WANG Xuan;LIU Qiao;YUAN Shoucai;RONG Cuicai;CHEN Wei;HUANG Jun;WANG Xingquan;LU XiuYuan(School of Physics and Electronic Information,Gannan Normal University,GanZhou 341000,China;Institute of Low Temperature Plasma Technology,Gannan Normal University,GanZhou 341000,China;Institute of Physics,Chinese Academy of Sciences,BeiJing 100089,China;Ganzhou People's Hospital,GanZhou 341000,China)

机构地区：[1]赣南师范大学物理与电子信息学院,江西赣州341000 [2]赣南师范大学低温等离子体技术研究所,江西赣州341000 [3]中国科学院物理研究所,北京100089 [4]赣州市人民医院,江西赣州341000

出　　处：《赣南师范大学学报》2020年第6期27-31,共5页Journal of Gannan Normal University

基　　金：江西省教育厅科学技术研究项目(GJJ170843);国家自然科学基金(22061002,52067002,51862001,11665005);江西省自然科学基金(20171ACB21049)。

摘　　要：采用三维电场仿真软件对100 keV超快电子衍射装置的直流光阴极电子枪在接入真空电极后的整体电场进行仿真,观察真空电极的工作特性及其对电子枪的影响.仿真结果表明,高压导线与真空电极连接的金属球表面电场约为4 kV/mm,处于易引发电晕放电的范围,放置PVC保护罩可阻挡其发展至空气击穿;真空电极大气压侧的陶瓷表面电场维持一较小值,不会发展出沿陶瓷表面的沿面放电;进入真空腔部分的电极导线表面电场最大值接近17 kV/mm,远超过电子枪阴极和阳极表面,极容易产生真空电子发射而导致真空击穿.在真空电极导线外套5 mm半径表面光滑金属长圆柱可有效降低表面电场,陶瓷材质效果更好,但由于陶瓷存在高电压下的间隙击穿和气孔击穿,陶瓷加工需严格.Three dimensional electric field simulation software is used to simulate the whole DC photocathode electron gun of 100keV ultrafast electron diffraction device after it is connected to high voltage by the vacuum feedthrough.The working characteristics of the feedthrough and the influence on the electron gun are observed.The simulation results show that the electric field on the surface of the metal ball connecting the high voltage conductor and the feedthrough is about 4 KV/mm,which is at a strength that can easily cause corona discharge.The PVC protective cover can prevent the corona discharge from developing into air breakdown.The electric field on the surface of the feedthrough ceramic in the atmosphere maintains a small value which would not develop creeping discharge along the ceramic surface.The maximum value of electric field on the surface of the feedthrough metal wire in the vacuum cavity is close to 17kV/mm,far exceeding the maximum electric field on the surface of the cathode and anode of the electron gun.It is very easy to produce a vacuum electron emission,which leads to vacuum breakdown.A 5mm radius metal cylinder with smooth surface on the outside of the feedthrough metal wire can effectively reduce the surface electric field.The ceramic is more effective.However,due to the gap breakdown and pore breakdown under high voltage,the ceramic cylinder require a high material process standard.

关 键 词：超快电子衍射 直流光阴极电子枪 电场仿真 真空放电 气体放电 

分 类 号：TL53[核科学技术—核技术及应用]