Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (8): 80405-080405.doi: 10.11889/j.0253-3219.2018.hjs.41.080405


L-M algorithm based explosive detection method by using the fast neutron

LI Jiangfeng1, SU Ming2, XIONG Zhonghua2, GAO Fan2   

  1. 1. Science and Technology on Surface Physics and Chemistry Laboratory, China Academy of Engineering Physics, Jiangyou 621907, China;
    2. Institute of Material Research, China Academy of Engineering Physics, Mianyang 621700, China
  • Received:2017-11-24 Revised:2018-05-11 Online:2018-08-10 Published:2018-08-15

Abstract: [Background] Compared with the traditional X ray detection method, use of fast neutron to detect explosives can get more accurate result which has attracted worldwide attention.[Purpose] This study aims to detect explosive by using the continuous fast neutron resonance spectrum of radioactive neutron source.[Methods] The Monte Carlo program Monte Carlo N-particle code (MCNP) was used to simulate the neutron spectrum of four kinds of explosives combining neutron time of flight method. The associated γ particle method can be used to measure the neutron time of flight (TOF) spectrum of 252Cf in practice, and levenberg-marquardt (L-M) fitting method was applicable to accurately calculate relative proportions of each nuclide. Based on the TOF methods of neutron energy spectrum measuring, the influence on the calculation results of time resolution, neutron flight distance, the thickness of the explosives and the statistical fluctuation has been taken into account for the measurement accuracy.[Results] The results show that L-M method can accurately calculate explosive nuclide ratio with high energy resolution, the maximum error was less than 10%. The energy resolution and thickness of the explosives increase the calculation error whilst the influence of statistical fluctuation can be eliminated by more than 106 neutron counting,[Conclusions] The exact nuclide ratio of the material can be obtained by fitting the fast neutron resonance continuous spectrum to realize the detection of the explosives. However, further research is needed to apply this method to the on-site measurement.

Key words: Fast neutron resonance, Explosive, Mont Carlo simulation, L-M algorithm

CLC Number: 

  • TL99