| With the increasing investment of our country in nuclear research,nuclear signals measurement system plays an increasingly important role in nuclear technology applications and nuclear physics.In twenty-first Century,the research and development of nuclear industry entered a new stage.The traditional nuclear energy spectrum measurement system is mainly based on analog circuits.Which used build analog circuit analysis platform to digital analysis nuclear signals.The signal through the resistance capacitance of the hardware circuit is easy to produce noise signal and disturb the original signal,so the traditional simulation system has not high resolution to the nuclear signal,and the processing result is not stable enough.Besides,the design of the traditional nuclear signal measurement system is complex,have to many logic circuit’s,and the finished product is to big.It is not suitable for the development of science and technology for the miniaturization and integration of measuring instruments.The modern nuclear spectrum measurement system adds digital signal processing technology,which has the characteristics of high integration,strong stability,fast data processing and so on.The nuclear energy spectrum measurement system is mainly composed of nuclear radiation detector,nuclear pulse amplification circuit,digital multichannel pulse amplitude analyzer,computer energy spectrum display software or embedded mobile display module,and power supply system.As the core of the nuclear energy spectrum measurement system,the digital multichannel pulse amplitude analyzer is widely used by the nuclear signal spectrum measurement system because of its digital controllable,high precision,high resolution and so on.Based on the digital multichannel pulse analyzer,a variety of measuring instruments adapted to various different nuclear spectrum measurement environments have been developed.The design requirements for the development of nuclear industry.As the core of digital multichannel pulse analyzer,the key to nuclear signal processing is the digital signal processing chip.The digital processing chips with higher integration level,better linearity,faster data transmission speed and less energy consumption have promoted the application of nuclear technology into a new stage,base on this,more and more different nuclear signal measurement system have been designed.The FPGA(field programmable gate array)is often selected as the core processor of the digital processing circuit of the nuclear signal,which undertake the tasks of waveform discrimination,data caching,filtering and forming.With the highly development of FPGA technology and embedded system,the FPGA which integration of embedded soft core is the new direction of embedded system development.Through SOPC Builder technology,users can customize their own soft core according to their own needs,that is,it has retained the advantages of the fast speed of FPGA operation,and can also take the soft core as the core of the system control.By this way can make complementary they functions,which show excellent performance in the development of systems that need algorithm and logic control.Combined with the above analysis,considering the requirements of system power consumption,integration,data transmission and cost in the nuclear radiation measurement environment.FPGA is selected as the only core processor of the paper nuclear signal measurement system for use of the the characteristics of the device:(1)The selected FPGA integrated Niso II Embedded soft core,FPGA and Nios Ⅱ soft core work together to achieve high integration of the system,energy consumption and cost control.(2)After processing,the data is processed with FPGA’s built-in dual port RAM for data caching.The dual port RAM has two sets of independent data lines,address lines and read and write control lines,allowing different devices to read and write the same storage unit at different times.The data caching method of double port RAM can avoid data transmission congestion and packet loss,improve the speed of system data transmission,and satisfy the requirement of real-time acquisition of energy spectrum data by nuclear spectrum measurement system.This paper aims at the requirement of system integration and high speed data transmission in the nuclear energy spectrum measurement system.The design of high performance nuclear spectrum data measurment system is realized by using the embedded control core based on Nios Ⅱ soft core and data caching of dual port RAM.Nios Ⅱ works as a core processor in collaboration with FPGA.Data is transmitted through dual port RAM cache,which realizes high-speed acquisition,real-time processing and flexible storage of nuclear signals.The system reliability is tested from various angles,such as component application,interface design and high speed signal processing.And have verified the real-time performance,integration and low energy consumption of the system.Finally,the NaI detector is used to continuously test the 1 3 7C s and 6 0C o of the laboratory,and the spectrum display of the nuclear signal is realized,besides,the accuracy of the measurement results is ensured.Through the experimental analysis,the instrument can realize the normal measurement of the nuclear energy spectrum,comfirm to the design features of high integration,high real-time,high performance and low energy consumption.It accord with the requirements of the development and design of nuclear technology applications,and the design requirements of the nuclear safety products.The makes an attempt on the application of the embedded system in the nuclear technology,and has been opened up the design idea of nuclear spectrum measurement system,which plays a positive role in the development of nuclear instruments. |
