Application Of Adaptive Filtering Algorithm On Nuclear Pulse Signal

Nuclear spectrum is the important information in domain of nuclear physics research, radiation detection and applications of nuclear technology, nuclear spectrum measurement technique has been a hot issue. Since the 1990s, with the rapid development of ADC and digital signal processing technology, digitization has become the main development direction of the nuclear analysis instrument. At present, the domestic and foreign related research institution has launched in-deep study in the digital pulse shaping instrument. Filter former method is the common method for the amplitude extraction of the digital nuclear pulse. Digital filtering shaping technique can not only replace the complicated analog filtering shaping technique and enhance the system stability, but also improve the flexibility and adaptability.The shaping of the digital nuclear pulse depends on the input of front-end circuit and the predominant noise.Howerer, the noise spectrum can vary over time for several reasons.whereas these techniques do not ususlly consider noise variations in real-time.To avoid this drawback and allow the use of self-adjusting transfer functions. This paper was to reduce the ADC sampling frequency as much as possible in order to reduce power consumption.In this paper,we proposed a technique for automatic synthesis of digital pulse shapers for high-resolution spectroscopy using an adaptive algorithm based on the LMS methods.The proposed shaper works as an adaptive digital Finite Impulse Response (FIR) filter. Domestic and foreign research institution the three forming modes:Trapezoidal shaping, Gaussian shaping, Triangle forming. In China, a lot of research units have carried on a lot of theoretical research and comparative analysis to three kinds of forming methods.In this paper, relying on science and technology major special instrument, this paper bases on the requirement of MOST Major Scientific Instruments and Equipment Development Project called as "Fast Measuring Instrument for Internal Radiation Contamination of Large Group of People" (Number:2012YQ180118) and conducts researchs on key technologies of digital nuclear shaping pulse. In this paper, the main research contents and results are as follows:(1)Focusing on the trapezoidal shaping, using a new tool called System Generator for the digital signal processing to the establishment of model and simulation. Firstly, introduce the system generator’s characteristics and advantages of modeling. Compared with the traditional development process of FPGA’s implementation algorithm, using the new method can greatly shorten the design cycle, reduce the difficulty of developer, save the cost of development. Firstly, introduce the system generator’s characteristics and advantages of modeling. Compared with the traditional development process of FPGA’s implementation algorithm, using the new method can greatly shorten the design cycle, reduce the difficulty of developer, save the cost of development.Firstly, introduce the design tool’s characteristics and advantages of modeling. Compared with the traditional development process of FPGA’s implementation algorithm.The new method can greatly shorten the design cycle, reduce the difficulty of developer, save the cost of development.(2)This paper expounds the principle of adaptive filtering algorithm and application field, and puts forward the solution of adaptive LMS algorithm of nuclear pulse filter forming. Firstly, the paper introduces the principle of adaptive LMS algorithm, the key steps for the implementation of adaptive LMS algorithm. Secondly, completed the LMS algorithm, and applied the algorithm to nuclear pulse filter shaping. This paper presents the structure, design and implementation of a new adaptive digital shaper for processing the pulses generated in nuclear particle detectors. The proposed adaptive algorithm has the capacity to automatically adjust the coefficients for shaping an input signal with a desired profile in real-time.