直接积分法研究电子光学成像系统的时间像差理论

提出了计算动态电子光学成像系统时间像差系数的新方法——直接积分法.以阴极面逸出的轴向电子初能为ε_z1（0≤ε_z1≤ε_0max）的近轴电子 轨迹为比较 基准,给出了时间像差的定义,详细叙述了直接积分法并给出求解动态电子光学成像系统时 间像差系数的积分表达式.τ变分法求得的二级几何时间像差系数必须求解微分方程, 而直接积分法求得的二级几何时间像差系数全部以积分形式表示,仅需进行积分运算,更适 用于成像系统的实际计算与设计. 关键词： 电子光学成像系统 阴极透镜 动态电子光学 时间像差理论

Theory of temporal aberrations for electron optical imaging systems by direct integral method

A new approach to calculate the temporal aberration coefficients of dynamic electron optical imaging systems is put forward in this paper. A new definition o f temporal aberration is given in which a certain initial energy of electron emi ssion along the axial direction ε_z1(0≤ε_z1≤ε_{0max< /sub>) as a cr iterion is considered. The new method for calculating the temporal aberration c oefficients of dynamic electron optical imaging systems named “direct integral method" is presented which gives new expressions of the temporary aberration coe fficients expressed in integral form. The difference between “direct integral m ethod" and “τ-variation method" is that the “τ-variation method" n eeds to solve the differential equations for the three of temporal geometrical a berration coefficients of second order, while the “direct integral method" need s only to carry out the integral calculation of them, which is more convenient a nd suitable for computation in the practical design.}