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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 developed ultrafast electron diffraction system consists of an ultrafast electron gun, a sample cell, an ultrafast readout system, a power supply system, and a vacuum system. The ultrafast electron diffraction system has high time resolution capability and strong detection capability. The photocathode is a 35 nm silver film deposited on a MgFB2 window, which is sensitive to 266 nm UV light, has high quantum efficiency and good chemical stability. Focusing on optoelectronics, there are two pairs of deflectors, one of which is used as a scanning plate in measuring the time pulse width, and the double MCP detector is used to enhance the intensity of the electronic image with a gain of 104 or more and a single electron detection capability. The total system time pulse width is designed to 358 fs.