Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (9): 90401-090401.doi: 10.11889/j.0253-3219.2015.hjs.38.090401


Simulation study on the converter of fast neutron imaging detector based on micro-channel plates

RAN Jianling1 LU Xiaolong1,2 MA Zhanwen1 WANG Wei1 ZHANG Jie1 WANG Jie1 MENG Fanliang1 ZHANG Yu1,2 YAO Zeen1,2   

  1. 1(School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China) 2(Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000, China)
  • Received:2015-03-17 Revised:2015-04-23 Online:2015-09-10 Published:2015-09-10
  • Contact: Ze-En YAo

Abstract: Background: As a unique non-destructive testing technique, fast neutron radiography has been widely concerned in recent years. However, the fast neutron imaging detector with higher resolution and higher detection efficiency still needs to be researched. Purpose: A new fast neutron imaging detector consisting of a polyethylene (PE) converter and a microchannel plate (MCP), is proposed for 14.5-MeV fast neutron radiography. Simulation studies are conducted for the design aim. Methods: The yields and energy spectra of the recoil proton produced by 14.5-MeV fast neutron on the PE converter are simulated using Geant4 code. The yields and the energy spectra of the recoil proton under the different PE converter thicknesses are presented in order to determine the converter efficiency and the reasonable thickness of the PE converter. Less than 14.5 MeV, fast neutron incident, the electronic gain process in MCP is simulated using Geant4 code. In order to analyze spatial resolution, the electron beam spot images are recorded after MCP. Results: The simulation results show that the thickness of PE converter should be selected in the range of 2.5 mm, and the converter efficiency is about 0.37%. The electron images show that the electron beam spot diameter is slightly bigger than MCP aperture. Conclusion: It can be predicted that the spatial resolution of the detector is close to MCP aperture.

Key words: Fast neutron radiography, Polyethylene converter, MCP, Electron gain, Spatial resolution