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Full-field transmission X-ray microscopy (TXM) in conjunction with X-ray absorption near edge structure (XANES) spectroscopy provides two-dimensional (2D) or three-dimensional (3D) morphological and chemical-specific information within samples at the tens of nanometer scale. This technique has a broad range of applications in materials sciences and battery research. Despite its extensive applicability, 2D XANES imaging is subject to the disadvantage of information overlap when the sample thickness is uneven. 3D XANES imaging combines 3D TXM with XANES to obtain 3D distribution information on chemical states. A 3D XANES imaging method has been established at the Shanghai Synchrotron Radiation Facility (SSRF) and has been used to characterize the structure and chemical state of commercial LiNixCoyMnzO2 (NCM, x + y + z = 1) battery powder materials. The imaging results provide a visual representation of the 3D chemical state information of the particles with depth resolution, allowing for the direct observation of 3D nickel oxidation. This paper will describe in detail the data acquisition, data processing, quantification and visualization analysis of 3D XANES imaging. [ABSTRACT FROM AUTHOR]

BackgroundDynamic micro-computed tomography (micro-CT) using monochromatic X-ray offers higher density resolution and lower radiation damage compared to that using white X-ray, however balancing its imaging spatial and temporal resolution is challenging. Currently, the reported highest temporal resolution of monochromatic X-ray dynamic micro-CT is 13.3 Hz with a detector effective pixel size of 5 μm.PurposeThis study aims to develop a monochromatic X-ray dynamic micro-CT system with a higher spatial and temporal resolution to meet the experimental needs of the fast X-ray imaging beamline (BL16U2) users at Shanghai Synchrotron Radiation Facility (SSRF).MethodsFirstly, an experimental system of dynamic micro-CT with the high flux density monochromatic X-ray from an undulator source was established by combination of a high-speed rotary stage and a large numerical aperture triple-lens fast X-ray imaging detection system on the BL16U2 beamline at SSRF. Then, a demonstration experiment with a fast-foaming polyurethane material as a sample was performed to examine the spatial-temporal resolution of this experimental system, moreover a quantitative analysis of the bubble motion during foaming process was performed.ResultsExperimental results of foaming process of the fast-foaming polyurethane material based on the monochromatic X-ray dynamic micro-CT system show that a temporal resolution of 20 Hz of the dynamic micro-CT was achieved with 15 keV monochromatic X-ray and an effective detector pixel size of 2.2 μm.ConclusionsThe developed monochromatic X-ray dynamic micro-CT system has a high spatial-temporal resolution and can perform four-dimensional quantitative analysis of complex motion systems, providing a powerful experimental research platform for users of BL16U2 beamline at SSRF.

BackgroundCustoms biosafety inspection is of great significance for maintaining ecological balance and protecting rare wild animals and plants.PurposeTo overcome the problem of poor contrast in traditional X-ray imaging systems for customs biosecurity inspections, an inspection instrument based on X-ray phase contrast imaging planned to be developed in this work.MethodsThe on-line phase contrast imaging method with high photon utilization efficiency was adopted in order to meet the requirements of high-efficiency data acquisition and fast imaging for the customs inspection. The protective shed shielding, security linkage and automatic sample stage were used in the instrument to ensure radiation safety in the inspection and the convenience of sample switching and adjustment. The methods of phase contrast micro-CT and three-dimensional micro-structure quantitative analysis were applied for biometrics recognition of specimens.ResultsA biometrics recognition instrument based on X-ray phase contrast imaging is developed. The test results of JIMA chart and actual samples show that the spatial resolution of the instrument is 3 μm and that the instrument enables high contrast imaging and quantitative analysis of weakly absorbing samples and can be used for the inspection of most biological specimens.ConclusionsThe instrument developed in this work provides a new tool for customs biosafety inspection. Due to its phase contrast imaging characteristics, the instrument can also be applied to the research of microscopic identification of Chinese medicinal materials, structural pharmaceutics and polymer materials.

BackgroundMassive projection data are produced by user experiments with the X-ray dynamic micro-computed tomography (CT) method on the X-ray imaging beamline at Shanghai synchrotron radiation facility (SSRF). CT reconstruction method based on central processing unit (CPU) serial computing is slow, which leads to a large backlog of experimental data. Graphics processing unit (GPU) is widely used in the field of high-performance computing because of its multi-core architecture and large-scale parallelization.PurposeThis study aims to speed up CT reconstruction by making use of GPU parallel computation for X-ray dynamic micro-CT on the X-ray imaging beamline at SSRF.MethodsAccording to computer unified device architecture (CUDA) programming standard, the back projection process of the filtered back projection (FBP) CT reconstruction algorithm was parallelized, and fast reconstruction of X-ray dynamic micro-CT was implemented on GPU of NVDIA RTX2080. CT reconstruction time was compared with that of CPU-based reconstruction method.ResultsThe comparison of CT reconstruction time shows that the CT reconstruction based on GPU parallel computing achieves about 200 times speedup compared with the CT reconstruction based on CPU serial computing, and the reconstruction time of a set of CT projection data is reduced from minutes to seconds.ConclusionsWith the powerful computing power of GPU, the fast reconstruction of X-ray dynamic micro-CT can be realized.

X-ray phase-contrast microtomography based on speckle tracking is an attractive method for non-destructive three-dimensional imaging owing to its simple setup and ability to yield absorption, refractive, and scattering images simultaneously. However, the edge-enhancement effect usually results in image artifacts or inaccurate phase retrieval, limiting the extensive application of this method in biomedical research and for low-Z materials. In this paper, a double-exposure method is introduced to solve this problem efficiently and accurately. Pure phase samples with various microstructures and densities and a biological sample with a distinct edge-enhancement effect were used to verify the effectiveness of the developed method. In an experiment performed using a polymer phantom with an evenly distributed density, 17 irregularly shaped particles with diameters ranging from 15 to 25 μm were successfully reconstructed with the effective elimination of the edge-enhancement effect. The results obtained for a sample composed of different polymer materials demonstrated that, in contrast with the traditional speckle-tracking method, the present method is able to discriminate materials with similar x-ray attenuations. Finally, experiments were performed using a dehydrated fish, which entail typical edge enhancement and a complex microstructure; notably, it was verified that the fine structure of the fish, including its fins and intestines, was reconstructed completely using the proposed method, whereas the standard speckle-tracking method was ineffective. In conclusion, the developed double-exposure method can serve as an efficient and accurate technique for the x-ray phase-contrast microtomography of samples comprising low-Z materials and complicated microstructures. [ABSTRACT FROM AUTHOR]