卢杰, 常乐, 陈益新, 姜云龙, 苏天宁, 刘倍宏, 赵航, 钱芸生, 刘健. 微光像增强器纳秒级荧光屏余辉时间测试系统[J]. 应用光学, 2022, 43(6): 1130-1137. DOI: 10.5768/JAO202243.0604012
引用本文: 卢杰, 常乐, 陈益新, 姜云龙, 苏天宁, 刘倍宏, 赵航, 钱芸生, 刘健. 微光像增强器纳秒级荧光屏余辉时间测试系统[J]. 应用光学, 2022, 43(6): 1130-1137. DOI: 10.5768/JAO202243.0604012
LU Jie, CHANG Le, CHEN Yixin, JIANG Yunlong, SU Tianning, LIU Beihong, ZHAO Hang, QIAN Yunsheng, LIU Jian. Development of afterglow time test system for nanosecond fluorescent screen of low-level-light image intensifier[J]. Journal of Applied Optics, 2022, 43(6): 1130-1137. DOI: 10.5768/JAO202243.0604012
Citation: LU Jie, CHANG Le, CHEN Yixin, JIANG Yunlong, SU Tianning, LIU Beihong, ZHAO Hang, QIAN Yunsheng, LIU Jian. Development of afterglow time test system for nanosecond fluorescent screen of low-level-light image intensifier[J]. Journal of Applied Optics, 2022, 43(6): 1130-1137. DOI: 10.5768/JAO202243.0604012

微光像增强器纳秒级荧光屏余辉时间测试系统

Development of afterglow time test system for nanosecond fluorescent screen of low-level-light image intensifier

  • 摘要: 荧光屏时间特性是评价像增强器性能的重要参数之一。微光像增强器纳秒级荧光屏余辉时间目前尚缺乏测试手段,基于传统像增强器余辉时间的测试方案,研制了纳秒级荧光屏余辉时间测试系统。该系统通过采样速率250 MHz的高速信号发生器完成对激光二极管光脉冲的激励,经由下降时间为0.57 ns的光电倍增管完成对荧光屏光信号的光电转换,µA量级的微弱光电流信号经放大及单端转差分电路,在AD9684中完成AD转换,随后荧光屏数字亮度信息经现场可编程门阵列(field programmable gate array, FPGA)后存储至DDR(double data rate)单元内,经上位机发出指令实现DDR内存的读取,通过USB3.0高速传输协议至上位机中。在数据处理中采用卡尔曼滤波及快速寻找下降沿算法,实现对采集数据的噪声滤波和余辉时间的准确测量。测试结果表明,该纳秒级荧光屏余辉时间测试系统可对具有超快光学特性的像增强器进行有效测试,P47型荧光粉的余辉测试结果达到118. 094 4 ns,重复度为2.08%。

     

    Abstract: The time characteristics of fluorescent screen is one of the important parameters to evaluate the performance of image intensifier. At present, there is no measurement method for the afterglow time of nanosecond fluorescent screen of low-level-light image intensifier. Based on the traditional test scheme of image intensifier afterglow time, a afterglow time test system for nanosecond fluorescent screen was developed. This system used a high-speed signal generator with the sampling rate of 250 MHz to complete the excitation of the laser diode light pulse, and a photomultiplier tube was used with the descending time of 0.57 ns to complete the photoelectric conversion of the fluorescent screen light signal. The weak photocurrent signal of µA magnitude was amplified and converted to a single-terminal differential circuit to complete the AD conversion in AD9684. Then the digital luminance information of the fluorescent screen was stored in the double data rate SDRAM (DDR) unit after field programmable gate array (FPGA), and the host computer sent instructions to read the DDR memory. The USB3.0 high-speed transmission protocol was used to transmit data to the host computer. In the data processing, the Kalman filtering and fast finding falling edge algorithm were used to realize the accurate measurement of noise filtering from collected data and afterglow time. The test results show that the proposed afterglow time test system for nanosecond fluorescent screen can effectively test the image intensifier with ultrafast optical characteristics. The afterglow test results of P47 phosphor reaches 118. 094 4 ns, and the repeatability reaches 2.08%.

     

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