Development of high-performance multichannel analyzer by using traditional pulse forming method and high-speed waveform sampling technology

Abstract

A high performance multichannel analyzer (MCA) based on traditional used pulse forming method and high-speed waveform sampling technology was developed in this paper for spectra analysis and radioactive measurement. The self-developed MCA is composed of conditioning part and processing part. The conditioning part including pole-zero cancellation, polarity conversion, programmable amplification, active integral filter, baseline recovery and peak holding is adopted to realize amplification, Gauss shaping and peak holding functions, while the processing part mainly including dither circuit, 16-bit 100 MHz high speed ADC and FPGA is employed to make waveform sampling and spectra acquisition. The performance including the differential nonlinearity (DNL), integral nonlinearity (INL) and energy resolution are studied by using precision sliding pulse generator, NaI scintillator detector and radiation sources. The results show that the DNL and INL of the MCA are better than 1.06% and 0.09% respectively, and the energy resolution measured with NaI scintillator detector at 0.662 MeV is about 7.82%. In addition, the DNL value depends on the appropriate selection of dither channels, and the optimal dither channel is 64 for the self-developed MCA in this paper. At last, the overall performance of the self-developed MCA is compared with a commercially available NIM plug-in type MCA, the results indicate that the MCA designed in this paper is obviously better than the commercially available MCA.