SBIR-STTR Award

To address NASA’s need for advanced non-destructive evaluation (NDE) sensors, Lookin, Inc. proposes to develop a transformative diagnostic tool to identify and localize visually inaccessible defects and damages in non-conductive coatings and thermal protection systems with significantly higher throughputs and over significantly larger volumes compared to what can be offered by existing NDE tools. More specifically, we propose to develop a contactless multi-pixel terahertz imaging system capable of capturing three-dimensional terahertz images of samples with a 5×5×20 cm3 volume and a scan rate of 100 Hz, while providing a signal-to-noise ratio of 65 dB and lateral/depth resolution of 100/10 µm. This terahertz imaging system is controlled by a data analysis algorithm that is capable of creating B- and C-scan images of the sample and automatically determining the position of the structural defects, such as cracks, voids, and delamination, within the samples. During the Phase I project, a laboratory prototype of the NDE scanner based of the multi-pixel terahertz imaging system will be developed by using a high-power terahertz source and a high-sensitivity terahertz focal-plane array. The prototype will be used to take terahertz images of non-conductive ceramic structures in laboratory environment to characterize tradeoffs between different system parameters such as scan rate, image depth, spatial/depth resolution etc. The data acquisition and analysis algorithms will be experimentally evaluated. During the Phase II project, a remote-controllable field prototype of the NDE scanner will be developed and the optimized system components will be packaged in a robust, portable platform suitable for in-situ NDE applications in field settings. The field prototype will be used to evaluate CMCs and other non-conductive composites used in aerospace systems and an advanced application software will be developed for the scanner with an easy-to-use guided interface. Potential NASA Applications (Limit 1500 characters, approximately 150 words): The primary application of the proposed terahertz scanner is non-destructive inspection of non-conductive ceramic-matrix composites for identification of inaccessible defects and damages on and below the surface with high resolution, precision, and throughput. It can be used in ground inspection facilities as well as in space for in-situ NDE and structural health monitoring of ceramic components of spacecrafts, which are usually used as thermal coatings. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): The proposed terahertz scanner is capable of inspecting many non-conductive polymers and composites including glass-fiber reinforced plastic, teflon, polyethylene, etc. Therefore, the same instrument can be used for NDE of many industrial products that heavily use CMCs and other non-conductive polymers, such as those in battery, auto, aerospace, construction, and oil & gas industries. Duration: 6

To address NASA’s need for advanced non-destructive evaluation (NDE) sensors, Lookin, Inc. proposes to develop a novel multi-pixel terahertz scanner, a transformative diagnostic tool to identify and localize visually inaccessible defects and damages in non-conductive coatings and thermal protection systems with significantly higher throughputs and over significantly larger volumes compared to what can be offered by existing NDE tools. During the Phase I SBIR program, Lookin performed feasibility studies and proved the suitability and superiority of its multi-pixel terahertz imaging systems for finding/localizing defects in materials commonly used as insulators in space applications, such as spray-on-foam insulator and cork, with a laboratory prototype multi-pixel terahertz scanner system. With the successful results obtained during the feasibility studies of the Phase I program, Lookin, Inc. proposes to extend its technological capabilities and develop a compact and portable field prototype multi-pixel terahertz scanner with enhanced resolution and scanning speed to be used for NDE of non-conductive coatings and thermal protection systems in field settings. More specifically, Lookin proposes to develop a contactless multi-pixel terahertz scanning system capable of capturing three-dimensional terahertz images of samples with a 5×5×15 cm3 volume at a scan rate of 10 Hz, while providing a signal-to-noise ratio of >60 dB and lateral/depth resolution of at least 100/10 µm. This terahertz imaging system is controlled by a data analysis algorithm that can create B- and C-scan images of the sample and automatically determine the position of the structural defects, such as cracks, voids, and delamination, within the samples. Anticipated

Benefits:
The primary application of the proposed terahertz scanner is non-destructive inspection of non-conductive coatings for identification of inaccessible defects and damages on and below the surface with high resolution, precision, and throughput. The instrument can be used in ground inspection facilities for NDE and structural health monitoring of non-conductive insulation materials of spacecrafts, such as spray-on-foam insulators and cork panels. The proposed terahertz scanner is capable of inspecting many non-conductive polymers and composites including glass-fiber reinforced plastic, teflon, polyethylene. Thus, the same instrument can be used for NDE of many industrial products that heavily use non-conductive composites and other non-conductive polymers, such as those in battery, auto, aerospace, construction, and oil & gas industries.