The Application Of High-speed PCIE Bus In Nuclear Signal Real-time Acquisition System

In the field of nuclear signal detection,nuclear signal acquisition is one of the important means to obtain energy information and time information of nuclear radiation field.A simple nuclear radiation pulse signal contains a lot of important information,including ray energy,type and time.Therefore,the accurate acquisition of nuclear signals on the nuclear radiation field analysis is of great significance.Normally,the core signal acquisition is the first data conversion,and then converted the digital signal processing.In the high-speed digital today,analog-to-digital converter(ADC)performance indicators continue to increase,while the data transfer rate also produced some requirements.In this paper,high-speed ADC and powerful FPGA,coupled with high-speed PCIE data transmission bus to build a real-time nuclear signal acquisition system.The system can not only obtain the core pulse signal amplitude information,but also real-time display of the acquired waveform,you can also complete the relevant algorithm in the PC real-time verification.At present,the detection of nuclear radiation field is usually measured in a way,including: front-end signal conditioning,signal acquisition,FPGA internal algorithm processing and the final spectrum and display.The whole process does not involve real-time display or storage of the original nuclear signal,which is not conducive to real-time monitoring of the signal or post-processing of the original data.This paper designs a set of real-time display,acquisition and storage system for nuclear signal.The topic of this paper comes from the national 863 project "high-precision energy spectrum detection equipment research and development"(subject number:2012AA061803).Design a set of high-performance Xilinx FPGA(XC7K410T)and high-speed PCIE bus core signal real-time acquisition system.Among them,the acquisition part of the use of 200 Msps,16-bit high-speed ADC sampling chip,the chip for the rise time in nanosecond and pulse width in a few hundred nanoseconds of nuclear signal has a good sampling effect,to meet the requirements of high-speed sampling.The data bit rate is 16 bits,and the data flow rate is 200Msps*16Bit =400MB/s.Data transmission using PCIE Gen2.0 standard,the measured transmission rate of about 3.0GB/s.To meet the above rates,set up a RAID disk array,the write speed through the HD Tune Pro test for the 800MB/s.For high-speed data transmission using DMA ping-pong way to complete,and each data exchange process of each link to analyze the cost,and design a reasonable set of DMA interactionmechanism.The driver part is developed using WinDriver 12.20,and its us-level interrupt response meets the acquisition requirements of the core signal system.Application software part of the design with Qt,in order to meet the real-time display and storage of nuclear signals,multi-threaded design,so that the smooth operation of the program.Finally,the system uses the system to collect the actual nuclear signal and verify the feasibility of the design.Real-time acquisition of the core signal waveform of the137 Cs detected by NaI scintillator is carried out and the complete original waveform is displayed on the application program and discussed.In addition,linearity was measured with a signal source to obtain a linearity of 0.9999.Using the sliding average algorithm to verify the feasibility of the platform,but also get good results.Experiments show that the scheme of real-time nuclear signal acquisition system based on high-speed PCIE is successful and feasible,and it has important impetus to the research of high-speed nuclear signal acquisition and real-time transmission,and has certain research value and application prospect.