The Key Technology Of High-performance EMCCD Imaging System

Electron multiplication CCD(EMCCD)is a true all-solid-state low-light imaging device,which belongs to the emerging device.Its high sensitivity,24-hour imaging and other technical features have very important applications in military and astronomical fields.Domestic research on EMCCD devices and imaging systems has overcome many key technologies,but there is still a certain gap with top foreign manufacturers.Aiming at the complicated driving requirements of EMCCD,this paper designed a general-purpose EMCCD imaging system.While not increasing the volume,it supports multiple models of EMCCD chips,laying a foundation for further research on the miniaturization of imaging systems.Based on the working principle of EMCCD,this paper analyzes the generation of noise and the coping methods of imaging system.According to its requirements for driving signals,a driving circuit based on FPGA is designed.The clock is driven by dedicated IC,and using DAC and filter amplifier circuit to generate sine wave as the multiplication drive signal of EMCCD The frequency,phase,and amplitude can be continuously adjusted,and the power consumption is low and more stable waveform.Aiming at the weak output signal of EMCCD,a preamplifier circuit is designed.The reset noise is removed by using a CDS circuit.After analog-to-digital conversion,it is processed by FPGA and output through Camera link.After the hardware is completed,code is written in the software using Verilog HDL language,and the corresponding waveform is generated and simulated and verified according to the complex timing requirements of EMCCD and the ADC.Accept digital signals from the ADC and process the output All modules are independently portable and have certain commonality,which can shorten the development cycle of other EMCCD cameras.At the end of this paper,the overall performance of the system is analyzed based on the realization of system functions,including parameters such as dark field noise,signal-to-noise ratio,dynamic range,modulation transfer function,and actual demonstration imaging effects.Comparative Experiment.The results show that compared with Andorra Luca camera and Hamamatsu camera C9100,the system has better parameters of dark field noise and signal-tonoise ratio than the two cameras,and the dynamic range and modulation transfer function parameters are close to those of the two cameras,which proves that in terms of performance and performance,the imaging system in this paper has reached a high level.