Monte-Carlo Simulation For Cosmic Ray Muon Tomography

In this thesis, the background and the present state on the cosmic rays muon tomography research were summarized briefly. The framework of the Geant4 toolkit and the Root program were introduced. In Root program, the POCA algorithm using the simplification method of equivalent single scattering was used to reconstruct the scattering angles and scatter positions associated with those angles. The scattering angle distribution and the most probable scattering angle were simulated in typical materials using 3GeV mono-energetic muon, and the curves of the most probable scattering angle vs different energy muon in several typical materials were presented. According to simulation results, the scattering basic principle and the muon tomography method on the high atomic number material under the low atomic number material background were analyzed.A sea level muon generator model was developed, and compared with the experimental data. The sample results showed that the developed muon generator model could describe the sea level cosmic ray muon spectrum very well.The scattering properties of 3GeV mono-energetic muon in Monitored Drift Tube (MDT) and Resistive Plate Chamber (RPC) were simulated and analyzed. The MDT is selected as the fitted detector style. The optimized structure and the material of MDT are presented.Finally, a muon tomography example on the reactor fuel elements was simululated using the developed Geant4 program and Root program. Several typical views on the muon tomography of the reactor fuel elements were presented under different conditions. The conclusion is that it's feasible to reconstruct the fuel elements using the muon POCA method. To get better imaging and shorten the time, however, the new algorithm and the new detector system with bigger capability and the higher detection efficiency should be developed.