COMPTON X-RAY BACKSCATTER DEPTH PROFILOMETRY FOR AIRCRAFT CORROSION INSPECTION

A new technique for detecting and measuring second-layer corrosion and metal loss in aircraft using Compton backscattered X-rays is presented. This technique gives a cross-sectional (through the thickness) view of aircraft sheet metal lay-ups and joints. It allows micrometer-accuracy dimensional measurements to be made as well as material identification of sub-surface (second) layers. This technique requires access to only one side of the structure; it is not a transmission (shadow casting) technique. Measurement accuracy to 0.025 mm (0.001 in.) has been demonstrated. Relative to other X-ray techniques, this depth profiling technique generates little ambient x-radiation. Hangar activities can continue uninterrupted in the vicinity of its use.