Design For A Range-gated ICCD And Its Control Circuit

Since the laser appears, the range gated imaging technology has a effect on distance, can effectively eliminate the influence of the backscatter of the floating particles in the atmosphere and the bias light. The technology can also improve the image contrast and the image quality significantly. Compared with continuous laser illumination imaging system,it has a further image distance. It is widely used in target detection, precision tracking and many other areas.Based on the range-gated imaging technology and its synchronous control technology, the structure of the range-gated ICCD and its operational principle has been analyzed. The components of the ICCD characteristics are also analyzed for improving the spatial resolution of ICCD, which can help develop high performance ICCD. The structure of image intensifier, the photocathode sensitivity, the characteristic of MCP and the delay time of the phosphor powder and there influences on the image intensifier has been analyzed. This paper designs a high-speed gated second generation image intensifier which is of short afterglow, high resolution and fast response time. A high performance range-gated ICCD was obtained by coupling a fiber taper to CCD. Theoretically analysis the coupling mode and coupling process, they also can make an effect on ICCD system. The MTF and system spatial resolution of the ICCD system are analyzed, which provide a theoretical basis for experimental test the performance of ICCD. The theoretical calculation of the ICCD spatial resolution is up to 32lp/mm.The ICCD need coordination and cooperation with the laser to achieve synchronization. In addition, the operating voltage and gain control are necessary. FPGA field programmable logic devices is employed to design the range-gated control circuit system, which can achieve digital control for ICCD by producing a nanosecond gating width. The system can also obtain clear images of objectives in different brightness and distance by adjusting the pulse width and delay time. In addition, the background noise is reduced and the dynamic range of imaging is increased. The gain of this system can be monitored and adjusted, which facilitate the gain control greatly. In this paper, the debugging of hardware and software of the FPGA control system are completed, and drawing the PCB board. Complete The functions of range gated control circuit, A/D, D/A are achieved. Also the design can achieve the FPGA chip communication with computer.A test platform has been built, the test result shows that a gating DC pulse which voltage is-200 V and width is 3 ns ~DC continuously adjustable is applied to achieve image intensifier gating. The highest gating frequency can reach to 300 kHz. The application of high frequency and narrow width pulse can effectively reduce image noise and improve image quality. The experimental test shows that the gain of the image intensifier is 10718cd/m2 lx when MCP voltage is 700 V and phosphor screen voltage is 5000 V and the system spatial resolution is 29.7 lp/mm...