The gated image intensifier has two function ,light gating and image enhancement .Coupled with a CCD device , it can constitute a high -sensitivity and high -speed image recording system , widely used in space and time resolved image diagnosis of inertial confinement fusion research .The photocathode gating voltage superimposed by the gate opening and closing time has a strong "limiter"effect ,which effects time within ns level , deeply affecting the image contour intensity profile in ns level time -resolved image diagnosis .This pa-per firstly analyzes theoretically the physical process leading the "limiter"effect , and carried out a simulation calculation [1] .Then some related experimental research was conducted .In the experiment , a pulsed laser with a wavelength of 532 nm and a pulse width of 300 ps is used as the light source .This experiment measures the o-pening /closing time of the image intensifier .The result shows that , the opening and closing time of the double tightly-stuck MCP image intensifier are approximately 1.8ns;for electrical pulses with a half -width of nearly 20ns, the exposure opening time of the MCP is about 30ns, demonstrating that the pulse width and the actual exposure time exist a certain difference .Further theoretical analysis indicates that in order to obtain a below sub-ns resolved image , we need a single tightly-stuck MCP image intensifier or to increase the thickness of the conductive substrate to sacrifice fluorescence transmission ratio as well as using other technical approaches .%门控型MCP像增强器具有光选通和图像增强两个作用，与CCD器件耦合组成高灵敏度高速图像记录系统，广泛应用于惯性约束核聚变研究中的时空分辨图像诊断。开门时刻和关门时刻叠加在MCP像增强器的光电阴极上的选通电压具有较强的“孔栏”效应，“孔栏”效应时间在ns级时间范围内，在ns级时间分辨图像诊断中对图像轮廓强度分布影响较大。本文首先从理论上分析了引起“孔栏”效应的物理过程，并进行了模拟计算[1]，然后进行相关的实验研究。在实验中使用波长为532 nm、脉冲宽度约为300 ps的脉冲激光作为光源，实验测量MCP像增强器的开门／关门时间，实验结果表明：双紧贴MCP像增强器的开门时间和关门时间约为1．8 ns，对于半宽度约为20ns电脉冲信号，MCP曝光开门时间约为30 ns，电脉冲宽度与实际曝光时间具有一定的差异。进一步的理论分析表明，为了获得亚ns级以下的时间分辨图像，需要采用单紧贴MCP像增强器或增加导电基体的厚度以牺牲荧光透过率等技术途径。
展开▼
