Conception of a High Resolution X-Ray Computed Tomography Device
Application To Damage Initiation Imaging Inside Materials

E. Cendre a, P. Duvauchelle a, G. Peix a, J.-Y. Buffière b, D. Babot a

a-INSA-Lyon, CNDRI Bât 303, 69621 Villeurbanne Cedex, France ; peix@insa.insa-lyon.fr

b-INSA-Lyon, GEMPPM Bât 303, 69621 Villeurbanne Cedex, France ; buffiere@gprhp.insa-lyon.fr

Abstract - X-ray computed tomography (CT) offers an unique opportunity for three-dimensionnal (3D) imaging inside most materials (metallic or macromolecular). A non destructive and very quantitative characterization can thus be attained. A 3D tomograph was conceived and constructed, allowing an adjustable spatial resolution with a cubic voxel, which size ranges from 8 to 200 µm. The tomograph is mainly constituted by a microfocus X-ray tube and an X- ray sensitive imager. The small size of the X-ray tube focus (around 7 µm) allows a geometrical enlargement up to 30. Two different imagers can be used : i) an image intensifier (Im.Int.) equipped with a CsI fluorescent screen and a Vidicon camera, ii) a low noise CCD camera (Charge-Coupled Device), equipped with a high-aperture lens and catching the visible image emitted by a terbium-doped gadolinium oxysulfide (Gd2O2S [Tb]) fluorescent screen. A mechanical testing machine was constructed that can be set on the turntable, in such a way to image damage initiation along successive states of strain, without dismounting the sample. A stress gauge and a linear displacement sensor allow to record the stress-strain curve. The machine can apply either a tensile or a compressive stress.

Keywords : X-ray, tomography, simulation, low noise camera.