Basics of industrial X-ray CT and case studies

This paper introduced the principle of industrial X-ray CT, features of CT manufactured by Baker Hughes Co., Japan (hereinafter, BH), advantages and scan examples of micro-focus CT, and contract business of BH. Since medical X-ray CT scans the living body, it is of utmost importance to reduce exposure dose. On the other hand, in industrial X-ray CT, the scan targets are mostly inorganic materials, so it is not necessary to suppress exposure dose. Industrial X-ray CT uses a magnified projection method using cone beams, and by moving the stage between the bulb and detector within the optical axis, it is possible to determine the enlargement/reduction and resolution of the projected image. The CT made by BH is composed of a granite strut and a rotating stage that uses air bearings to minimize the accuracy fluctuations due to thermal expansion and the distortion due to aging. It has the systems to remove scattered rays that cause noise, using both hardware and software. The data inconsistencies and noise that occur during CT scan and reconstruction are called artifacts, and are suppressed using various filters near the radiation source. As actual examples, this paper introduced a lithium-ion battery and a stepping motor. This company is entrusted with a large number of 3D scan measurements using various industrial X-ray CTs. (A.O.)