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研制了一台电子能量损失谱仪用的中高能电子枪。其产生的电子与原子、分子发生碰撞,通过谱仪收集、分析散射电子的动量和能量,可以获得靶的电子结构和碰撞动力学信息。该电子枪结构简单,由热阴极、栅极、阳极、聚焦极和偏转板组成;电子能量可调范围大(1-3 keV),操作简单。为了获得最优的束流条件,利用SIMION电子光学软件模拟了电子发射源大小和初始发散角对靶点处的束斑大小和束流发散角的影响。在电子能量为1.5 keV条件下,实验检验给出在离电子枪出口27 mm处可获得束径约为0.95 mm、束流发散角约0.93°和束流强度6.27mA的电子束,满足电子能量损失谱仪的使用要求。
A high energy electron gun for electron energy loss spectrometer was developed. The generated electrons collide with atoms and molecules, and the momentum and energy of the scattered electrons are collected and analyzed by the spectrometer to obtain the electronic structure and collision kinetic information of the target. The electron gun has a simple structure and consists of a hot cathode, a grid, an anode, a focusing pole and a deflection plate. The electron energy can be adjusted in a large range (1-3 keV), and the operation is simple. In order to obtain the optimal beam conditions, the influence of electron emission source size and initial divergence angle on beam spot size and beam divergence angle at the target was simulated by SIMION electronic optical software. At electron energy of 1.5 keV, experimental results show that electron beam with electron beam diameter of 0.95 mm, beam divergence of about 0.93 ° and beam current of 6.27 mA can be obtained at a distance of 27 mm from the exit of the electron gun. Instrument requirements.