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Synchrotron radiation X-ray computed tomography (CT) provides information about the three-dimensional electron density inside a sample with a high spatial resolution. Recently, the need to examine the internal structure of materials composed of light elements, such as water and carbon fibers in resins, has increased. Small density differences in these systems give low X-ray contrast; segmentation methods suited for this type of problem are necessary. Machine learning is typically used to analyze CT data, and a large amount of training data is required to train a machine learning model. Conversely, transfer learning, which uses existing learning models, can develop a learning model using only a small amount of training data. In this study, the synchrotron radiation X-ray CT images of an epoxy resin containing water have been analyzed using transfer learning as the validation of a method for analyzing low-contrast CT data with high accuracy. Circular domain structures in the resin have been observed using the X-ray CT method, and statistical information about these structures has been successfully obtained by transfer learning-based analysis. Here, transfer learning is performed using twelve slices within an X-ray CT 3D image, demonstrating that low-contrast synchrotron CT data can be segmented with a small amount of training data.

An insertion device capable of switching the operation mode between helical and figure-8 undulators, and thus referred to as a helical-8 undulator, has been developed. It has the advantage that the on-axis heat load can be kept low regardless of the polarization state, even when a high K value is required to lower the fundamental photon energy. This is in contrast to conventional undulators in which the on-axis heat load tends to be significantly high to generate linearly polarized radiation with a high K value, and optical elements can be seriously damaged. The principle of operation, specification and light source performance of the developed helical-8 undulator are presented together with further options to enhance its capability.

Abstract Adhesion is a technology for assembling carbon fiber (CF) reinforced polymer (CFRP), enabling them to maintain their lightweight and high-stiffness properties. Despite the importance of adhesion, the lack of a molecular-level understanding of the adhesion mechanisms has limited the reliability of adhesion for use in next-generation aircraft and automobiles. Here, we focused on the chemical-state distribution at a practical adhesive interface composed of an epoxy-based adhesive film bonded to an epoxy-based CF matrix. By fluorinating the OH group, we succeeded in visualizing the chemical state at the CF-matrix/adhesive interface using soft X-ray microscopy. The soft X-ray images exhibited a decrease in OH-related signals at the interface due to the local chemical interaction at the epoxy-epoxy adhesive interface. We also found that the N and O Kα signals were observable at the CF's surface, indicating the presence of nitrogen- and oxygen-containing functional groups. Based on these observations, we discuss the molecular-level adhesion mechanism at the CF-matrix/adhesive interface.

Recently, material strength measurements have been often performed by combining mechanical material characterization and lattice diffraction experiments using hard X-rays. When X-ray diffraction experiments are performed simultaneously with tensile tests, plastic deformation due to stress can be analyzed at the lattice level. Although this evaluation procedure is suitable for materials such as metals, it does not provide information on molecular state changes and stress-induced electronic state transitions in polymer materials. Combined with an evaluation system in the electron energy band involved in chemical bonding during the tensile stress application, the systems would advance our understanding of adhesion states such as interfaces in polymer materials and composites. Here, we developed a MEMS-based system aimed at implementing a Raman spectroscopy imaging system and a stress control system on a soft X-ray absorption spectroscopy and photoelectron spectroscopy microscopy (PEEM) system. We prepared two types of MEMS device: a double-sided beam structure device and a three-point tensile testing device. A three-point tensile MEMS was integrated into a micro-Raman spectroscopy system to perform micro-Raman spectroscopy measurements during the tensile testing of a silicon beam. As for the double-sided beam structure MEMS, it was successfully introduced into the synchrotron radiation PEEM system and its operation was confirmed in vacuum. [ABSTRACT FROM AUTHOR]