Experimental Demonstration of X-Ray Fluorescence CT Using a Spatially Distributed Multi-Beam X-Ray Source

Abstract

X-ray fluorescence computed tomography (XFCT) is a high-sensitivity imaging modality for high-atomic elements such as gadolinium (Gd) or gold (Au). In order to improve the contrast of x-ray fluorescence (XRF) signals in the raw projection data, common XFCT systems use single-pixel x-ray spectrometers to record XRF photons stimulated by the pencil-beam x-ray source and achieve line-by-line scan of the whole object by translating the x-ray source or the object. However, this kind of design results in waiting time of the translation device. One improvement would be to replace the traditional x-ray tube with a spatially distributed multi-beam x-ray source and scan the whole object by switching the exposure of each focus. In this study, we present a design of the XFCT system using a spatially distributed multi-beam source, and a XFCT imaging experiment was performed to investigate its feasibility. Each cold cathode of the x-ray source used in this study was made of carbon nanotubes, and each focus was independently controlled by the electronic control system. The incident beam was collimated by a pinhole array to produce a pencil-beam source. The object scanned by the system was a polymethyl methacrylate (PMMA) cylinder (8 cm in diameter) with Gd (20 mg/ml) and I (100 mg/ml) insertions. Results show that the distribution of iodine (I) and Gd in a PMMA phantom was successfully reconstructed, but the imaging performance was limited by the collimation and exposure mode of the current distributed x-ray source. The practicality of the current distributed x-ray source used for XFCT scan and further optimization of the proposed system are discussed according to the experimental results.

Constraints on the Geometry and Gold Distribution in the Black Reef Formation of South Africa Using 3D Reflection Seismic Data and Micro-X-ray Computed Tomography

“…This has resulted in a new characterization workflow that includes multiscale (e.g., meso-, micro-or nanoscale) characterization techniques (da Costa et al, 2022). With the rapid advancement of ore characterization tools and techniques in the 2D and 3D environments, such as X-ray fluorescence computed tomography for quantitative chemical, mineralogical and textural characterization of ores (Chen et al, 2020), it is of utmost necessity to move toward dry laboratories (data-centric and computation-heavy laboratories) and modernized data management practices. This type of environment will provide the ideal technology and expertise to analyze both old and new data to extract multi-timescale information.…”