X-ray computed tomography (CT) critical nondestructive evaluation (NDE) of nickel-hydrogen spacecraft batteries

Summary form only given as follows. This paper focuses on the methods and techniques of applying CT X-ray analysis to nickel-hydrogen spacecraft cells and batteries. Computed tomography X-ray analysis provides high-resolution quantitative imaging of internal battery components and structures, including metals, alloys and nonmetallic composites. Boeing is equipped with two independent scanning systems-a large part scanner and a high resolution small part scanner. Evaluation by the 201 system is capable of large components measuring as large as 68 inches in diameter, 72 inches high, and weighing up to 5000 pounds. The system utilizes a 2.5 MEV pulsed linear accelerator source to generate high-energy X-rays to a 128 discrete element linear detector array. Computed tomography (CT) produces a two-dimensional density map (or tomogram) of a cross-sectional slice of an object's interior. Faults within materials can be located and analyzed without touching the object. Though pioneered in the medical diagnostic industry, Tomography provides important benefits for industrial nondestructive testing (NDT) and nondestructive evaluation (NDE). CT offers several advantages over other NDT/NDE techniques, like film radiography, real-time radioscopy, and ultrasonics. CT scanning provides easily-interpreted images of objects with complex geometric configurations and/or compositions. CT scan images are less sensitive to contrast degradation caused by radiation scattering effects. Dimensional information is accurate within several thousandths of an inch. Quantitative information provided by CT scanning, in digital form, provides fast, accurate, and repeatable computer analysis, rather than requiring subjective visual interpretations by individual operators.