中文摘要：

优化设计了一套超快电子衍射系统．用轨迹追踪法讨论了光电子在阴极上有150fs的时间弥散量，及其静态、动态特性（电子束斑、时间弥散、方位角、倾角）在超快电子衍射系统中的传输情况．用Monte Carlo方法对光电子的初始状态进行抽样、用有限差分法计算二维、三维空间电场分布，用有限元法计算磁场分布．

英文摘要：

An ultra-fast electron diffraction system has been designed. The static and dynamic characters of an electron pulse with 150 fs temporal dispersion are studied during its transmission in the whole ultra-fast electron diffraction system, including the size of the electron spot, temporal dispersion, distribution of azimuths and elevation angles. The initial status of the photoelectrons are put down by Monte Carlo method, both the two dimensional and three dimensional electric fields are calculated by finite difference method and the magnetic flux are calculated by finite element method.