X-ray computed tomographic scanner for non-medical use

Two types of x-ray computed tomography scanners (x-ray CT's) developed by the author for use in the engineering and archaeological areas are briefly outlined. One is designed for non-destructive analysis of steel samples, which was installed at the First Technical Laboratory of Nippon Steel Corporation. This CT was designed based on a CT for medical use marketed by Toshiba Corporation and consisted of a high voltage generator, x-ray measurement chamber, console and computer. Compared to medical CT's, the equipment uses high voltage to permit analysis of steel samples of up to 50 mm in diameter. The sample is rotated unlike ordinary medical CT's in which the x-ray source and detector rotate. The use of sophisticated colimeters achieves a high plane resolution of 0.25 mm x 0.25 mm. Transmitted x-rays are measured in eight different directions and processed by the computer to give cross-sectional images on the CRT display on the console. The other CT presented here, which is currently being constructed at the Fuchu Plant of Toshiba Corporation, is designed for analysis of historical (archaeological) samples. The CT is equipped with two radiation sources, one for x-ray and the other for gamma ray, to serve for different samples. Some measurements made with the CT for steel samples are presented. (Nogami, K.)