The Design and Experimental Results of Fiber Optic Plate Coupled Indirect Electron Detector

According to the characteristics of transmission electron imaging in the transmission electron microscope, an indirect electron imaging detector coupling a fiber optics plate with a CMOS camera was designed. By varying the thickness of the phosphor layer and the aluminum film, respectively, it was found that under the same conditions, thinner phosphor layers could obtain brighter images than the thicker ones. Within a small range, changing the thickness of the aluminum film had little effect on image brightness. Considering the detection efficiency of the microchannel plate (MCP) for high-energy electrons, attempts were made to place the MCP in front of the phosphor screen. Test results showed that the MCP effectively increased image brightness, with a 30-fold increase in screen brightness at a working voltage of 700 V compared to the situation without the MCP. Considering the ability of the MCP to shield X-rays and its relatively low replacement cost, it may be a new choice for indirect electron detectors.