为评估像增强器对强光的响应特性, 开展了连续激光对像增强器的辐照实验, 分析了激光辐照对其增益特性的影响。实验结果表明: 持续增加激光功率, 直到光阴极处激光功率密度达到点饱和阈值激光功率密度的8×104倍时,仍未出现像元串扰现象, 表明像增强器出现了增益饱和, 其输出光强受限。建立了像增强器的微通道板等效电路模型, 分析了微通道板的增益特性, 得到微通道板线性增益允许的最大入射电流约为1.64×10-10 A。该结果非常接近实验测量值, 表明通道损失的电子得不到及时补充是增益饱和的主要原因。

To study the influence of laser radiation on the performance of an image intensifier, the irradiation experiment of CW laser on the image intensifier was carried out and the effect of laser irradiation on its gain characteristics was analyzed. Experimental results show that no pixel crosstalk phenomenon is found as the increase of the laser power until the light illumination arrives 8×104 times of the illumination for point saturation, meaning that the gain of the image intensifier is saturated and the output light intensity of image intensifier will not increase indefinitely. The equivalent circuit model of the microchannel plate of the image intensifier was established and its gain characteristic was analyzed. The maximum current for linear gain, got from this model, was approximately 1.64×10-10 A, which was very close to experimental data, indicating that the charge extracted from the microchannel wall cannot be replenished in time is the main reason of gain saturation.