Design of X-ray backscatter imaging system for vehicle detection

摘要

Design research of X-ray backscatter imaging system for vehicle security was carried out, aiming at the demand of accurate and rapid detection of contrabands. The influence of the chopper mechanism on the imaging resolution and the solid angle of the flying point beam was simulated, while the parameters and structure of the chopper mechanism were designed. The imaging resolution of the backscattering system is about 8 mm and the solid angle of the flying point beam is about 6.4×10~(-5) sr. Based on the X-ray energy deposition and luminescence efficiency, the effect of detector thickness and lead doped on the detection efficiency with different energy was investigated. A calculation model of luminous flux for backscatter detection was established and the influence of detector parameters on scattered X-ray luminous flux was analyzed, also the length of the detector was determined. The results show that it is more reasonable to use the lead-free plastic scintillator with thickness of 50 mm and length of 2.5 m as the backscattering detector for the X-ray backscattering system used for scanning of vehicle bottom, which can meet the demand of security inspection of vehicle bottom.