Experiments in Compton scatter imaging of materials with wide-ranging densities using a low-activity gamma source

Abstract

A low-activity Compton scatter imaging device employing a 1.4 mCi 133Ba gamma source has been used to detect 6 mm diameter voids in materials of very different densities and structural types. Two-dimensional histogram images have been obtained of sections of steel, steel covered with simulated marine growth, medium-density polyethylene and an inorganic ceramic cement, all containing 6 mm diameter simulated voids. The image contrast is large enough to differentiate these voids from statistical noise in runs of reasonable duration for practical source intensities, therefore making the technique promising for a variety of applications to small-component inspection. The images obtained are corrected for the effects of photon attenuation and in one case the image has been compared with a non-corrected one.