X-RAY COMPTON BACKSCATTERING TECHNIQUES FOR PROCESS TOMOGRAPHY - IMAGING AND CHARACTERIZATION OF MATERIALS

Non-destructive evaluation by Compton scattering using an industrial x -ray tube allows three-dimensional (3D) imaging of materials. The x-ra y tube and the detector are set on the same side of the object. Thus, non-destructive evaluation of the wall of a tank, even when it is full , is possible without the requirement for the x-ray beam to cross the whole object. Several applications were tried in our laboratory. Besid es 3D imaging, a method allowing thickness measurement of a wall was d eveloped, which was especially suitable for multilayer compounds. The accuracy is +/-0.01 mm. Compton scattering techniques also allow point -by-point density measurements in the near-surface zone of any compone nt (even dense and bulky ones). An accuracy of 1% was achieved for lig ht composite materials and also for dense components (p approximate to 6.5) provided by powder metallurgy. A new application allows us to pe rform 3D imaging using a linear accelerator (6 MeV) as the photon sour ce. Thus, testing can be performed inside a tank, even through a thick and dense wall (8 mm of steel).