Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (6): 60204-060204.doi: 10.11889/j.0253-3219.2015.hjs.38.060204

• LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS • Previous Articles     Next Articles

Digital n/γ discrimination measurement of low intensity pulsed neutron

TIAN Geng1 OUYANG Xiaoping1 QU Hongguang1 ZHANG Xianpeng1,2 LIU Jinliang1 LI Haitao1   

  1. 1(Northwest Institute of Nuclear Technology, Xi’an 710024, China) 2(School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China)
  • Received:2015-02-10 Revised:2015-04-16 Online:2015-06-10 Published:2015-06-05

Abstract: Background: The traditional measurement methods in which the detectors are working in counting mode or current mode all have limitations in the measurement of low intensity pulsed neutron. Purpose: We aim to establish a method for low intensity pulsed neutron measurement to acquire the spectra of energy and time by digitalizing and analyzing the fast current pulse generated by detector as each single neutron induced. Methods: A digital pulse shape discrimination (DPSD) system for low intensity pulsed neutron measurement has been developed, which employs wideband digital oscilloscope as data acquisition device. With BC501A liquid scintillator detector, the system can acquire and store the waveforms of neutrons and γ-rays, and discriminate neutrons from all waveforms by DPSD algorithms. The system has two operation modes as “continuous acquisition” and “acquisition window with time stamp” for different event rates according to the intensity of pulsed neutron. Results: The function of pulse height analysis of neutrons is achieved, and time information of neutron’s arriving can be acquired by the analysis of the position of the waveform in the record or the time stamps. Experiment has been carried out with Am-Be neutron source with the operation mode of acquisition window, and the neutron pulse height spectrum, time spectrum and n/γ discrimination spectrum have been acquired. Conclusion: The spectra of energy and time of low intensity pulsed neutron can be measured by the digital method which employees wideband digital oscilloscope and digital signal processing algorithms, and has the advantage that all original waveforms of neutrons and γ-rays can be stored for further analysis.

Key words: Pulsed neutron, Neutron spectrum, Time spectrum, n/γ discrimination, DPSD