A resin gauge for performance testing of X-ray CT and its calibration by multiple orientation measurements

An accurate and traceable performance testing of the X-ray computed tomography (XCT) is crucial for the application of the XCT in various industrial fields. For the performance testing of the XCT, we proposed a novel gauge with spheres embedded in a cylindrical resin. The proposed gauge is free from the artifacts caused by the gauge structure, and the spheres can be arranged at any position of the gauge. Additionally, the gauge can be placed with different orientations and it can be produced at an economical price. We verified the feasibility of using the proposed gauge as a reference standard, in terms of the coefficient of thermal expansion and secular change of the resin. Furthermore, we developed the associated calibration method for the gauge through multiple orientation measurements using the XCT. From the results, the proposed gauge can be calibrated with an un-certainty of 1.9 & mu;m when the gauge size is 30 mm.