强流微束斑电子束系统的研究和设计计算-西安交通大学三T空间.PDF

第 26 卷 　第 6 期 真 　空 　科 　学 　与 　技 　术 　学 　报 　　　　　　　 　　　　　　　　　　　 2006 年 11 、12 月 CHINESE JOURNAL OF VACUUM SCIENCE AND TECHNOLOGY 435 　 强流微束斑电子束系统的研究和设计计算 郭小立 　唐天同 　康永锋 　任 　岩 (西安交通大学电子物理与器件教育部重点实验室 　西安 　710049) Generation and Calculation of Intense Electron Beam with MicroSpot Size Guo Xiaoli ,Tang Tiantong ,Kang Yongfeng and Ren Yan ( ) Key Lab of Electronic Physics and Device of Ministry of Educations , Xi ’an Jiaotong University , Xi ’an , 710049 , China 　　Abstract 　A novel technique has been successfully developed to generate intensive electron beam with microspot size and an electron μ beam with a current of 1. 96 mA and a spot radius of 4. 2 m has been produced. The technical innovation is the design of a new electrostatic magnetic lens set ,which includes an axially asymmetrically distributed magnetic field peaking at the crossover of the electron beam ,and a well controlled electric lens with retarding potentials generated by auxiliary electrodes which are located in the area of strong magnetic field to effec tively reduce the defocusing caused by spacecharge repulsion. In addition ,Vlasov Equation has been modified to numerically calculate several key physical quantities ,including the evolution of the current density distribution of the electron beam ,the excitation of the lens and the initial conditions of the injected electron beam. We found that the welldesigned side pole gap lens and the auxiliary electrodes make it possible to generate intense electr