Abstract
Conventional direct radiography may fail to successfully produce images of corrosion in large pipes containing liquid and in tanks because the attenuation can be very high. It also fails when either side of the object is not accessible. These limitations do not exist in backscatter imaging because it is a one-sided imaging technique. However, backscatter imaging can be slow. In this study, the feasibility of a new backscatter imaging system based on a moving collimator that can produce images quickly is studied. Backscattered radiation from a broad-beam industrial X-ray machine is collimated by a special collimator to allow only parallel scattered radiation to pass and reach the image plate. Because part of the backscattered radiation can be stopped by the collimator septa, the collimator is put into motion; this allows a complete image to be revealed. An electro-mechanical system is designed to move the collimator either in steps or continuously. The distance, speed and direction of the movement are controlled by a smart motor using LabVIEW. Images of Polyvinylchloride (PVC) and aluminum objects are shown. Moving collimators can be added to existing radiographic systems to make them useful for both direct and backscatter imaging.