Design And Test Of Data Acquisition System On The Space High-Energy Neutron Detector

The space particles with high energy cause radiation damage on spacecraft, and threat the health and life of astronauts. With the development of China's manned space program, it's very necessary to detect and research space high-energy particle radiation deeply. Data acquisition(DAQ) system is an important part of the space particle detector system. Through signal processing and data acquisition,we can achieve the characteristic information, like direction, type, energy etc. of target particle.This thesis mainly designs and builds a data acquisition system which is based on waveform digitizer with high speed and high resolution, for fast plastic scintillation detector array. And this data acquisition system has been successfully applied to experimental tests. This thesis studies and analysis the working principle of high-speed waveform digitizer, designs the way of data transmission in the DAQ system, completes the hardware building in system and the synchronization measurement connections. Also, it studies the way of processing digital data by FPGA firmware. Using the data acquisition software realizes the data caquisiton and online concidece acquisition.The DAQ system built in this thesis realizes acquiring data without dead time, through adopting the circulating register and method of high-speed sampling for detector signal. This thesis realizes ADC sampling frequency from 1GSPS to 2GSPS, through making the waveform digitizer working in DES mode by the data acquisition software based on the standard FPGA firmware, which improves the temporal precision of pulse waveform processing, timing precision and minimum coincidence counting time window have been 0.5ns. It also implements the online coincidence counting measurements, which reduces the background trigger rate and the total amount of data and improves data transmission efficiency of this DAQ system. Using coincidence counting method and cutting the background method improves the detector energy resolution.Finally, this thesis builts and debug the data acquisition system for data acquisition, and calibrates the fast plastic scintillation detector unit after data processing and anysising. Results show that designed data acquisition system can satisfy the requirement of fast plastic detector data acquisition;the EJ-200 detector has good time response and its output pulse rise time is less than 10 ns; the light output response of detector on electronic between 0.662 Mev and 2.615 Mev is linear.