Research Of Signal Readout System For Waveguide-Gate Structure Based On Calibrated Modulation

Complex detection is becoming increasingly significant for space target recognition and regional perception.At present,there are mainly two modes of complex detection.One mode of complex detection is achieved in exchange for time-sharing receiving and processing of signal.The other mode of complex detection is obtained at the cost of reducing the detection performance of dim targets through signal power distribution into different receiving units.In order to solve the above problems,the calibration method of electron beam modulation and the readout system of position sensitive detection signal in the waveguide-gate film structure of complex detector are researched in this paper.The following parts is mainly included:In the first part,the gain self-saturation effect of microchannel plate and the principle of electron beam loss in multi-plate cascade process are analyzed.The model of composite detector with waveguide-gate structure is proposed and its working principle is discussed.The physical process of composite detection is illustrated by the study of spatial resolution,response time and noise factor of the device.The constraints between the parameters of waveguide gate structure and the detection capability of the whole electronic optical system are revealed through theoretical analysis and functional formulas.In the second part,according to the conductivity theory of continuous metal film and detection efficiency of the microchannel plate with film,the calibration model of waveguide gate film structure modulation degree is built.The Monte-Carlo statistical method is used to simulate the trace of a large number of low-energy random incident electrons into gate films,and then two factors——film thickness and electrode voltage affecting the special electron beam modulation of the gate are defined.The preparation process of nano-composite film is explored.The controllable preparation and characterization of waveguide gate photomultiplier structure are achieved.It is provided the technological basis for the calibration of modulation.In the third part,the influence of multi-path broadening and additional noise caused from waveguide gate structure on the detection accuracy of the anode is revealed.While taking gain and frequency response into account,the preamplification and linear main amplification mechanism are studied.The signal-to-noise ratio of the signal waveform is increased with the fourth-order Chebyshev low-pass filter structure based on Sallen-Key topology under the condition of additive Gauss distribution noise superimposition.A multi-channel parallel peak holding circuit is designed.The digitization method of positionsensitive readout signal of waveguide gate structure detector is discussed.The digital hardware system is designed,including analog-to-digital conversion module,data buffer module and Ethernet interface module.In the fourth part,A measurement system for modulation calibration of waveguide gate film structure in vacuum is built to verify the realization of compound detection function based on electron beam modulation and shunt.The sampling relationship of electron beams between gate and anode under different acceleration voltages is calibrated by double measurement.Under a certain accelerated electric field,a direct charge extraction method of the position sensitive anode is introduced.The quasi-Gauss pulse with 2μs pulse width and 200 kHz frequency is obtained by the designed signal readout circuit,and then the image information is obtained through the data acquisition system.The results in this paper is supposed to be a reference for theoretical research and engineering realization on combination of imaging and communication of space target detection equipment in the future.