HIGH RESOLUTION DIGITAL RADIOGRAPHIC NDE OF LAMINAR BONDS IN COMPOSITE MATERIALS USING DISCRETE DETECTORS

THIS PHASE I SBIR PROGRAM PROPOSES TO DETERMINE THE FEASIBILITY OF USING HIGH-RESOLUTION DIGITAL RADIOGRAPHY (DR), LAMINOGRAPHY, AND COMPUTED TOMOGRAPHY (CT) TO EXAMINE LAMINAR BONDS IN COMPOSITE SAMPLES SUPPLIED BY THE ARMY. THE PROJECT WILL UTILIZE DISCRETE, SOLID-STATE X-RAY DETECTORS DESIGNED AND BUILT BY BIO-IMAGING RESEARCH, INC. THE PHASE I PROGRAM WILL ALSO RECOMMEND A PRELIMINARY DESIGN FOR SUCH A SYSTEM. SIMPLE TANGENTIAL DR SHOULD ALLOW EXAMINATION OF CIRCULARLY SYMMETRIC OBJECTS WITH RESULTS SUPERIOR TO ANY OTHER FILM OR FILMLESS INSPECTION TECHNIQUE. LAMINOGRAPHY, ALSO KNOWN AS CONVENTIONAL TOMOGRAPHY, AND CT UTILIZING THIS DETECTION TECHNOLOGY, SHOULD ALLOW LAMINAR PLY IMAGING OF FLAT PLANES. IMAGING IS ACHIEVED BY MOTION OF THE SAMPLE THROUGH A COLLIMATED X-RAY FAN BEAM OR VICE VERSA. DISCRETE DETECTORS PROVIDE DR WITH HIGH CONTRAST RESOLUTION AND A DYNAMIC RANGE OF 16 BITS (65,536 GRAY LEVELS). THESE DETECTORS CAPTURE NEARLY 100% OF THE X-RAYS TRANSMITTED FOR EXCEPTIONAL QUANTUM EFFICIENCY. LINEAR ARRAYS OF THESE DETECTORS CONSIST OF DISCRETE CHANNELS OF OPTICALLY ISOLATED SCINTILLATION CRYSTALS INDIVIDUALLY COUPLED TO INDEPENDENT PHOTODIODES. INDIVIDUAL CRYSTALS WITH SPECIFIC ACTIVE WINDOW WIDTHS AND PACKING DENSITIES MAKE IT POSSIBLE TO SPATIALLY RESOLVE INDIVIDUAL PLIES IN TYPICAL COMPOSITE STRUCTURES THAT ARE BETWEEN 125 AND 300 MICRONS THICK. THIS SPATIAL RESOLUTION IS OFFERED WITHOUT THE BLOOMING ASSOCIATED WITH OTHER FILMLESS IMAGING TECHNIQUES.