Modeling of x-ray backscatter imaging system using MCNPX code

X-rays have wide applications in medicine, industry, scientific research, security issues, etc. The use of X and gamma rays to inspect cargo, cars, as well as persons has about 50 years old and today they are widely used around the world to prevent the carrying of weapons and drugs. In general, nowadays transmission systems have been more developed than back-scattering imaging. On the other hand, x-ray backscatter imaging system have special and unique applications due to their inherent advantages. Also, because the entire imaging system is on one side of the object, mobile imaging is more possible for this type of modality. In this research, an x-ray backscatter imaging system was modeled using the Monte Carlo method by means of MCNPX code. First, a 160 kV X-ray tube was modeled then the tube output was examined with the spectrum of the commercial tube. In the next step, the geometry of the device, the detection system and the scanned object were designed and modeled. The results showed that it is possible to detect bubbles with a diameter of 5, 10 and 20 mm for an object at a distance of 5 cm.