Nonscanning Compton Backscattered X-Ray Corrosion Evaluation and Monitoring System

To address the U.S. Air Force need for detecting the presence of corrosion in hard-to-access areas of aircraft without lengthy and expensive disassembling, Physical Optics Corporation (POC) proposes to advance the development of a new, affordable, Nonscanning Compton Backscattered X-ray Corrosion Evaluation and Monitoring (COXEC) system for in situ non-destructive evaluation (NDE) of aircraft multilayered aluminum alloy and composite parts with complicated geometry. The system is based on the POC-developed Compton Imaging Tomography technique which enables reconstructing full three-dimensional structure of an object with precise spatial localization of corroded areas inside the object using a set of two-dimensional Compton-backscattered X-ray images of the object. The system hardware requires only one-sided access to the object, and provides 100-200 micrometer resolution and <0.5% sensitivity in density difference. In Phase I, POC demonstrated feasibility of the COXEC technology for NDE of aluminum parts with complex geometries by fabricating and testing a TRL-4 prototype. In Phase II, POC will develop a TRL-6 prototype system that will be evaluated by the Air Force to determine its performance in detection and localization of general and pitting corrosion, the amount of general surface corrosion, and the density and depth distribution of any corrosion pitting. BENEFIT: Military applications of the COXEC system will include in situ in-field NDE/NDT of different aircraft multilayered aluminum/aluminum alloy parts with complicated geometry, parts of helicopters, airplanes, missiles, etc., for determination and localization of general and pitting corrosion, and flaws (voids, inclusions, cracks), and other performance-limiting defects and to ensure proper assembly of components. The COXEC system can also be used by the U.S. Air Force, Army and Navy as NDE/NDT system for parts containing different heterogeneous materials (e.g., explosives, adhesives, electronic components, composites, plastics). An expansion of most of the techniques developed under COXEC Phase II can transition to the commercial application of Compton imaging tomography NDE/NDT systems, i.e., flaws and corrosion detection of complicated geometry heterogeneous structures of civil aircraft, spacecraft, rockets, light vessels, etc. Other COXEC applications will include detection of hidden improvised explosive devices (IEDs): the COXEC system can create the 3D X-ray image of IED and completely represent the IED’s internal structure to help bomb squads neutralize the IED safely. With minor modifications, a COXEC-like system can also be used for detection of hidden objects inside airframe cavities in fuselages, wings, etc.