Spatial resolution of synchrotron x-ray microtomography in high energy range: Effect of x-ray energy and sample-to-detector distance

Abstract

Spatial resolution of 3D images obtained by synchrotron X-ray microtomography technique is evaluated using cyclic bar patterns machined on a steel wire. Influences of X-ray energy and the sample-to-detector distance on spatial resolution were investigated. Relatively high X-ray energies of 33-78 keV are applied due to the low X-ray transmission of transition metals. Best spatial resolution of about 1.2 µm was observed at the sample-to-detector distance range of 20-110 mm and at the energy range of 68-78 keV. Several factors such as X-ray scattering and diffraction phenomena affecting the degradation of spatial resolution are also discussed.

W-Concentration 3D Mapping in SKH51 Steel by Dual-Energy K-Absorption Edge Subtraction Imaging

“…These profiles were fitted in Sigmoid function, and then the full width of half maximum (FWHM), which is one of index that represents spatial resolution, was produced from first derivative of the fitted Sigmoid function. 11,12) The obtained FWHM were 10.1 μm, 5.2 μm and 1.0 μm in sample-todetector distance of 2 mm, 20 mm and 65 mm, respectively. The theoretical spatial resolution 12) was obtained in the 65 mm sample-to-detector distance.…”

“…However, effect of scattering and diffraction on spatial resolution has been reported for imaging in steels. 11,12) Therefore, sample-to-detector distance may affect concentration brought by absorption edge subtraction imaging. Sample-to-detector distance was set 2, 20 and 65 mm, and then its effect was examined in this study.…”

“…Recently, utilizing stable high-energy beam and adjusting an effect of scattering and diffraction by sample-to-detector distance, however, the SR-CT with theoretically limited resolution is available in also steels, in which the sample is same size with aluminum alloy. 11,12) In this study, three-dimensional W-concentration mapping has been attempted in steels by applying absorption edge subtraction imaging with high energy X-ray in synchrotron radiation facility. The effect of sample-to-detector distance on spatial resolution is known in the SR-CT using high energy X-ray.…”

3D Fracture Behaviours in Dual-phase Stainless Steel

“…It has been reported that in a relatively high X-ray energy range, preferential forward scattering occurs, 12,14) which results in a remarkably low signal-tonoise ratio and spatial resolution when the sample-to-detector distance is less than 50 mm. 12,14) On the other hand, the ring artefacts observed above a sample-to-detector distance of 50 mm are gradually annihilated in the long-distance images. This may be attributable to degradation in the spatial resolution.…”

“…14) However, most of these studies have focused on simple damage evolution behaviour in continuum solids. Two-dimensional observation of longitudinal sections has been supplementarily employed for identifying microvoid nucleation mechanisms.…”