FPGA And LabVIEW-based Nuclear Signal Acquisition And Display System

Energy spectrum measurement is one of the main means of nuclear physics research. The development of the spectrometer is also constantly introducing new technology and method. Using virtual instrument software technology and digital technology is a new trend now.According to spectrum measurement problem, this paper studies a set of energy spectrum measurement system based on FPGA and Lab VIEW. The structure adopts FPGA-field programmable logic devices as the core controller, using 14 * 512 the size of ping-pong cache to cache the digital quantity transformed by AD, adopting USB2.0 technology to rapidly transmit signals, USB has the characteristics of hot plug, transmission signal to the PC can do real-time "plug and play". Using Lab VIEW virtual instrument technology gathers the digital quantity of USB transmission for display.Paper work includes three parts:(1) the traditional technology is adopted to form the front end of the signal processing circuit;(2) the conversion/technology and data acquisition circuit composed of FPGA technology, form the hardware part of the fully digital acquisition system;(3) the data processing part of the virtual instrument software technology.Front-end signal processing part contains the traditional signal amplification, forming and accumulation of refuse, etc. This part of the technology is already relatively mature, although that is certain selectivity on the adaptability of signal source(suitable for a particular source/detector), but more suitable for the goal of this thesis: portable, miniaturization of spectrum acquisition equipment.Section contains data acquisition circuit transformation as well as data buffer storage/technology. This part actually constitutes the hardware part of the fully digital data acquisition system. Paper uses the FPGA programmable logic devices for medium, according to the characteristics of the USB serial port transfer rate high finish data buffer storage and transmission. Using FPGA as the control unit system, designed a FIFO ping-pong cache, namely two FIFO buffer alternations of data read/write, to adapt to the randomness of nuclear detection signal and USB data transfer.Virtual instrument technology can use desktop computer powerful graphical environment, establish a replacement hardware panel virtual graphical man-machine interactive panel, at the same time, complete instrument control, data analysis and result display. Paper uses current popular software of virtual Instrument--Lab VIEW Laboratory Virtual Instrument Engineering Workbench),in the form of data flow, according to the program block diagram of the data flow between nodes in determine the execution sequence of function, design a spectrum measurement system based on Virtual Instrument software Lab VIEW as the development platform. System using NI- VISA for USB bottom drive, considering various program structure, finally designs timing module with the sequence structure and the While loop, the sub vi parameters can cache reuse and multithreaded programming. Optimizing the software interface with Lab VIEW built-in controls, the energy spectrum display software is easier to operate. Display software completes spectrum smoothness, finding peak and the calculation of the net area and display. Data acquisition part of the work, in order to further implement the energy spectrum of the fully digital acquisition system laid a certain foundation.The last part of the paper compares the way digital spectrum measurement, by studying the way of digital spectrum measurement; digital spectrum measurement scheme is given.