A SOFTWARE SIMULATION TOOL DEDICATED TO THE DESIGN AND EVALUATION OF X-RAY BACKSCATTER SYSTEMS V.Rebuffel, J.Tabary, J.Rheinlaender

Backscatter X-ray technique is particularly convenient for the inspection of single-sided access objects, in order to detect subsurface defects or control subsurface layers thickness. This well known technique can benefit today from recent developments in detectors technology. Backscatter technique requires many parameters: relative geometry of source, detector and object, and associated collimation. In order to help the design of backscatter systems, we have developed a software simulation tool, able to predict the backscatter signals for given systems and objects. Theoretically, such a simulation should be performed based on Monte Carlo code to manage multiple scatter interactions. We propose a version based on analytical computation, allowing fast simulation, and a modified one using partially a Monte Carlo code, if more accuracy is required. Experimental measurements are compared to simulation. The proposed tool can also help the interpretation and analysis of backscatter signal for complex objects. Key-words: X-ray imaging, backscatter, Compton scattering, simulation, inspection, single-sided access objects, subsurface defects.