微通道板的饱和效应对条纹相机动态范围的影响分析

Influence analysis of saturation effect of microchannel plate on dynamic range of streak cameras

条纹相机通常采用微通道板的内增强或外增强这两种方式来提高信号探测阈值,也由此引入了微通道板饱和效应对系统动态范围的限定.通过一个非连续电阻电容打拿极链的通道模型,对微通道板的饱和效应进行了描述,说明了在条纹相机中,微通道板输入输出的线性范围限定于通道的贮存电荷,即使是在外增强方式中采用低阻抗微通道板,传导电流的补偿作用也极其有限,微通道板内增强和外增强条纹相机应具有相近的动态范围,低阻抗微通道板仅在高重复率的连续拍摄时方可发挥功效,同时还说明了微通道板增益的正确设置对条纹相机动态范围的重要影响.

The streak cameras which with an internal or external microchannel plate （MCP） image amplification has a significant enhance- ment on the detect signal threshold, but also induces the saturation effect of MCP to limit the dynamic range of streak camera. The saturation effect of MCP is described through the channel multiplier model of a discrete resistance capacitance dynode chain, explain- ing that the input output linear range of MCP which in both the two amplification method is depend on the charge restored in the channels the contribution of compensate effect which comes from the bias current is very limited, even using a low restistance MCP in the external method streak camera, so the streak cameras with an internal and external MCP image amplification should have equivalent dynamic range, low resistance MCP only function if a rapid sequence shots is required, and MCP gain was set up properly is critical for the dynamic range of streak camera.