X-Ray Compton Backscattering Computed Tomography System for One-Side in situ High-Pressure Submarine Hull Inspection

To address the DARPA need for non-acoustic tomography for NDE/NDI of the structural integrity of base metals and elements of submarine hull structures (even through hull treatments), Physical Optics Corporation (POC) proposes to develop a new industrial X-ray Compton Backscattering Computed Tomography (CBCT) system. CBCT is based on registration of multiple Compton backscattered X-ray 2D-images of an object, to restore its 3D-image using a POC-developed inverse Radon transform for Compton backscattered X-rays. Innovations in the real-time inverse Compton Radon transform algorithm, a high-energy X-ray (2-4 MeV) generated by an industrial portable linear accelerator, apodized Gaussian aperture array, and capillary scintillator will enable CBCT to perform in situ one-side NDE/NDI of high-pressure submarine hulls, even without a thorough surface cleaning of the hull coating. The CBCT system can be easily adapted for handheld usage, and for underwater applications. CBCT has a penetration depth of 2-3 in. of steel, with field-of-view ~1.5 ft x 1.5 ft, spatial resolution ~0.01 in., and density resolution no more than 2 percent, which directly address the DARPA requirements. In Phase I, POC will demonstrate CBCT system feasibility by determining its resolution, registration, and errors. In Phase II, POC will design and test a CBCT system prototype.