中文摘要：

研发的超快电子衍射系统由超快电子枪、样品室、超快读出系统、电源系统，以及真空系统等组成，该超快电子衍射系统具有较高的时间分辨能力和较强的探测能力．光电阴极是蒸镀于MgFB2窗上的35nm的银膜，该阴极对266nm的紫外光比较敏感，有较高的量子效率，又具有很好的化学稳定性．用短磁聚焦系统来实现对光电子的聚焦，有两对偏转板，其中的一对在测量时间脉宽时用作扫描板．用双MCP探测器来增强电子图像的强度，其增益在10^4以上，具有单电子探测能力．系统的总时间脉宽设计为358fs.

英文摘要：

The designed electron diffraction system consists of an ultra-fast electron gun, a sample chamber, a readout system, a power supply system, and a vacuum system, and it bears such unique characteristics as high energy, high temporal resolution, and high detection capacity. The photocathode is of a 35 nm Ag film deposited on an MgF2 glass disk, and it is sensitive to ultraviolet light with wavelength of 266 nm. A magnetic lens is used to focus the electrons. Two pairs of electric deflection plates are used in the X and Y directions respectively to control the movement of the electrons, and one pair of them will act as a scanning plate while measuring the pulse width of electrons. The sample chamber is made of stainless steel, and in the middle of the chamber there is a specimen holder, capable of shifting in three dimensions and turning around its axis. The diffraction pattern recording system has a very high detecting efficiency, and even a single electron could be detected. A cascade MCP detector is used to ensure an electron gain reached to 104. The electron gun is in a vacuum system of 10^-4 Pa. The whole gun is shielded by a μ-metal sheath. The designed temporal resolution of the ultra-fast electron diffraction system （UED） is about 358 fs.