| Explosives detection is a matter of great concern to all countries in the world,and it has become an inevitable trend to strengthen the detection of explosives.In military conflicts and terrorist attacks,a variety of improvised explosives are often used for explosion damage,which brings great hidden danger to people’s safety in many areas.It is an important task to quickly and effectively identify hidden explosives.Neutron detection technology is often used to distinguish between conventional substances and potentially explosives with its advantages in non-destructive detection,and it has been widely welcomed in recent years.This article mainly focused on the explosives hidden in the soil and building walls,and carried out related research.According to the requirements of the detection object,a corresponding detection system is designed for explosives identification.In this study of landmine detection,an improvised landmine detection system based on D-T sealed neutron generator was built and modeled by MCNP5 code.The feasibility of using FNA for landmine detection was evaluated by a combination of experiment and simulation.The results show that the background radiation levels greatly limits the ability of FNA to detect landmines.Inspired by previous efforts,the tagged neutron technology with strong background suppression ability is proposed for landmine detection.A landmine detection system was designed using MCNPX code,and the shielding materials of the system were optimized and selected.The simulation results of graphite and "water + graphite" samples were analyzed from time selection,specific voxel energy spectrum information.The influence of the soil humidity was studied for the landmine buried at different depths,and the ratio of C/Si and C/O peak areas of explosive spectra and soil background spectra was calculated and compared.Finally,the library least-squares method is used to unfolded the landmine detection energy spectra into the contribution of basic elements.The results of the unfolded element spectra can effectively distinguish explosive materials in the detected soil.In the detection of explosives in building walls,an experimental detection system based on tagged neutron method was developed for explosive detection,and the system was modeled using MCNPX code.The simulated samples of TNT and ammonium nitrate under different conditions were tested by the system.The experimental results were compared with the simulation results and have good consistency,which verifies the reliability of the simulation result.On this basis,the simulation of RDX and Tetryl explosives hidden in different thickness walls was carried out.The simulation results show that by recording the gamma ray count in the 4.44 Me V area,the experimental system can detect the 300 g explosive hidden in a wall with a thickness of no more than 10 cm. |
PDF Full Text Request