飞秒电子衍射系统的设计(英文)  

Design of an Ultra-fast Electron Diffraction System

作　　者：吴建军[1] 田进寿[1] 王俊锋[1] 邹玮[1] 赛小锋[1] 赵宝升[1] 刘运全[2] 梁文锡[2] 张杰[2] 

机构地区：[1]中国科学院西安光学精密机械研究所,西安710068 [2]中国科学院物理研究所,北京100080

出　　处：《光子学报》2006年第12期1827-1831,共5页Acta Photonica Sinica

基　　金：Supported by National Natural Science Foundation ofChina(10527002)

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辩能力和较强的探测能力.光电阴极是蒸镀于MgFB2窗上的35 nm的银膜,该阴极对266 nm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104以上,具有单电子探测能力.系统的总时间脉宽设计为358 fs .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.

关 键 词：超快电子衍射 微通道板 磁聚焦 时间分辩 

分 类 号：O463.1[机械工程—光学工程] TN16[理学—电子物理学]