Development Of Domestic High Energy Electron Gun

Surface science technologies are developing rapidly,which provide us powerful tools to study the condensed matter Physics from electron,atom and molecular level.RHEED(Reflected High Energy Electron Diffraction)is composed by a high energy electron gun and a phosphor screen,and it is a typical method in the field of surface analysis because of its diffraction pattern and in situ analysis.A suitable electron gun for RHEED shall produce high intensity electron beams with variable high energy,small beam spot size and adjustable emission angle.In order to make up for the deficiency of our country in the field of high energy electron emission,the domestic high energy electron gun which is suitable for RHEED is developed,on the basis of synthesizing all kinds of electron guns.In this paper,the initial model of the electron gun is designed firstly,and with the aid of finite element analysis software CST simulate electron beam trajectory.The purpose of simulation is to optimize the key parameters of each electrode of the electron gun.And then,under the condition of ensuring the optimal parameters of the electrodes,the structure design of the electron gun is completed.The structure is mainly composed of electron emission components,focusing components,deflection components and differential vacuum pumping unit.Finally,we also give a brief overview of the design of the electron gun power supply,and give the prototype of the power supply.In order to verify the feasibility and effectiveness of the electron gun design,a set of ultra-high vacuum system is set up to carry out the relevant test experiment.Test results show that the electron energy up to 30keV,the relationship between acceleration voltage and emission current is found keeping direct proportion,the electron beam can be deflected more than 5° and the beam size can be focused to less than 100?mBy the measured Si(111)single crystal,a good electron diffraction image is obtained.The measured parameters of the high energy electron gun have been fully met the design standards,which can be used to carry out real-time in-situ surface atomic structure and dynamic analysis.The successful research and development of the high energy electron gun has improved the comprehensive technology level of our country in the field of small and high energy electron emission,and promoted the development of domestic surface analysis instrument.