The Key Technology Of Scientific-grade General-purpose Electron Multiplying CCD Imaging System

With the continuous development of EMCCD image detector and the increasing demand for the localization of core devices,the demand for the performance parameter test and evaluation of EMCCD devices in China is increasingly urgent.However,due to the variety of EMCCD devices,the number of pins,array scale and driving sequence of different devices are different.Therefore,it is urgent to develop a universal EMCCD imaging system to improve the consistency and comparability of performance parameter testing.Aiming at the above problems,a universal EMCCD imaging system is designed in this paper,which can provide a universal platform for testing performance parameters of multiple EMCCD devices.The design of general hardware driver circuit based on FPGA is the focus of this paper.By analyzing the working principle of EMCCD devices and the common characteristics of the driving signals,the hardware driving circuit design is completed to meet the requirements of the driving ability and number of multiple EMCCD devices.At the same time,according to the output characteristics of EMCCD devices,the relevant dual sampling circuit is used to complete the ANALOg-digital conversion,and the EMCCD image acquisition and Camera link transmission are realized through FPGA.As long as the corresponding CCD chip board is replaced,it can support the drive signal generation of many EMCCD devices.Around the hardware circuit,write Verilog language programs and develop generalized software programs.Focus on parametric drive timing design for different EMCCD devices,complete the image acquisition,median filter processing,video output and other necessary program modules.A set of erial communication instruction protocol is formed to realize the functions of driving timing sequence and flexible configuration of circuit parameters.Based on the hardware circuit and software program mentioned above,the whole imaging system is carried out board cascade modulation,circuit test,signal test and imaging demonstration,and a number of science-grade EMCCD device driving imaging are realized.Finally,on the basis of imaging,the multiplicative gain,integration time and median filter are tested.The test results show that the imaging system meets the design requirements in terms of function and performance,and the imaging effect is relatively ideal.The imaging system can realize multiple EMCCD devices using the same hardware circuit,the same FPGA driver program,and the program control is flexible and simple,with universality and practicality.