X-ray analysis has made remarkable progress over the 120 years since the early 20^th century. At every critical turning point in its history, researchers in X-ray analysis and the related fields have been successful in providing new seeds that can bring a significant impact on all other scientific fields, and in giving suitable solutions to the unsolved scientific mysteries. For further development in the future, what points will be important? The author will discuss the necessity and perspectives of multi-scale and multi-dimensional X-ray analysis, based on 32 years' experience at a national research institute specializing in materials science.

Synchrotron X-ray analysis are suitable tools for the research and development of batteries, because their high permeability of substances enables in-situ electrochemical measurements without destruction of battery cells. These experiments are able to obtain numerical dataset at once. However, investigation of the important factor from numerical data spent an enormous amount of time because of the spectral features correlated with material features was understood by the theoretical calculation, and/or the knowledge of researchers. The applications of measurement informatics for the analysis of numerical dataset is expected to lead efficiently data analysis as well as to high-quality data acquisition. Here, we introduce the applications of the measurement informatics for the measurement data, which were data-driven analysis of the in-situ XAFS/XRD, and higher resolution 2D imaging XAFS. The relationship between the X-ray analysis data and the voltage change of the rechargeable battery cell was analyzed by sparse estimation methods. The obtained features were similar to the conclusions from the previouse report, and implied even the possibility of extracting hidden features of X-ray analysis dataset. The signal-to-noise ratio of the spectra was improved by using image denoising in an unsupervised learning model with Noise2Noise, which enabled high-resolution mapping of the electrode reaction distribution.

Because some confusion in Japan today regarding the term standard deviation, the actual situation was explored by actually measuring X-ray fluorescence. The results again showed that the theoretical standard deviation based on conventional statistical variation is valid. It was experimentally shown that the so-called “theoretical” standard deviation based on the counting rate is consistent with the conventional theoretical standard deviation divided by the measurement time.

The phenomenon that the measured standard deviation is greater than the value calculated from the “standard” deviation expressed as a counting rate was not observed in this measurement.

The background of X-ray fluorescence (XRF) spectra of a lead-containing resin measured at 3 milliwatts of X-ray tube input are (i) experimentally removed by a three-dimensional polarized zirconium secondary target experiment and (ii) numerically removed by the Akima interpolation calculations. Two methods are compared. Both methods were shown to effectively reduce the background. The XRF spectra with low background obtained by the two methods are different based on their principles, as well as the target elements. Polarization optics showed that XRF spectra of good S/N can be obtained even with an X-ray tube input of 15 milliwatts. We propose a new discrimination method of overlapping peaks by iterative calculation for Akima interpolation.

The performance of Real-time X-ray Fluorescence microscope (R-XRFM) using an elliptical monochromator of symmetric X-ray optics or asymmetric X-ray optics is evaluated by ray tracing. In particular, the performance in the microanalysis region of 40 μm square is compared with that of the case where the Johansson type and the Johann type monochromator of the symmetric X-ray optical system are used, and it is shown that the spatial resolution of the symmetric elliptic monochromator is equivalent to that of the Johansson type. In the case of an asymmetric elliptic monochromator with a magnification of 2, there is a decrease in sensitivity, but the spatial resolution is superior to that of the Johansson type, and it is shown that normalization of X-ray intensity for each pixel is unnecessary depending on the target accuracy in practical use. The appendix explains the algorithm of the ray-tracing method when symmetric elliptical type, asymmetric elliptical type, Johansson type or Johann type monochromators is used for R-XRFM.

One of the problems in photoelectron spectroscopy is the charging effect for insulator samples, which causes spectral shift and distortion. One way to reduce the charging effect is the measurement under a gas atmosphere. Here, we attempted to eliminate the charging effect by introducing Ar gas in near-ambient pressure hard X-ray photoelectron spectroscopy measurements of h-BN and LiF powder samples. The distance between the sample and the aperture cone head (normally 0.3 mm), d, was increased for more effective charge compensation. The charging was eliminated at d=1.2 mm and Ar pressure of 1800 Pa for h-BN and d=1.8 mm and 1600 Pa for LiF. In addition, since the spectrum of the introduced Ar gas is also affected by the charging of the sample, it was found that the degree of charging of the sample can be evaluated from the shape and the binding energy of the Ar gas spectrum. This is useful in determining whether the asymmetric inner-shell spectrum obtained from an insulator sample is intrinsic or due to inhomogeneous charging.

Sample holder for stretching of rubbers was made to investigate the structure of rubber polymers by soft X-ray absorption spectroscopy. Incident-angle-dependent XANES spectra of the stretched rubber were measured in C K and O K regions. From the C K-XANES, it can be clarified that rubber polymers partially take vertical orientation and that the vertically-oriented structure was reduced in the stretched rubber. From the O K-XANES, it can be clarified that the rubber samples involve carbonyl sp²-O atoms taking the similar orientation as the sp³-C atoms.

X-ray absorption imaging for elemental identification was studied. A secondary target was applied to change the energy of the X-rays. X-ray absorption images were taken with the energies above and below the X-ray absorption edge using optimal secondary targets. X-ray absorption images were acquired with a short exposure time of a few seconds with a highly sensitive X-ray camera. A metal foil sample composed of Al, Cu, and Ni was analyzed. To obtain the X-ray elemental image of Ni, two X-ray absorption images are required above and below the Ni K-edge. Thus, X-rays of Cu Kα and Zn Kα were prepared by using Cu and Zn plate as the secondary targets. Finally, the Ni elemental image was obtained by subtracting two images. Furthermore, the threshold energies controlled with the X-ray camera were applied for elemental imaging. It was demonstrated that an X-ray elemental image of Ni was obtained using a single secondary target such as brass material without changing the secondary target.

The Government of Japan issued the ALPS-treated water discharges into the sea. To satisfy international standards, total amount control, and domestic regulation standards for tritium discharge into the sea, it is desired to establish a technology for total and continuous measurement of tritium. The liquid scintillator method, which is a conventional measurement method, cannot measure the total amount and continuously, so it is not possible to shut off the discharge in an emergency. In this development, the use of a solid scintillator, the GAGG scintillator, enabled total and continuous measurement. In addition, we succeeded in measuring tritium in a short period of time and succeeded in developing a continuous total amount of tritium measurement device that enables emergency response when ALPS-treated water is discharged into the sea.

Residual hydro-desulfurization (RDS) is an essential process toward the efficient use of petroleum resources. In this study, we performed X-ray tomography on two RDS catalysts, cat-A and cat-B, to analyze the relationship between the catalyst's inner structures and their lifetimes. The lifetime of cat-B was 15% shorter than that of cat-A. Our findings showed that the number of closed pores in cat-B greatly increased after use. The median pore diameter of cat-B was 40% smaller than that of cat-A, which indicates that pore blockage was more likely to occur in cat-B. Using CFD analysis, we also found that the permeability of cat-B after use was much smaller than that of cat-A. In addition, the pores of cat-A seemed to act as percolation paths more effectively than those of cat-B. Overall, our findings clarified the differences in inner structures that affect the lifetime of RDS catalysts.

X-ray micro-computed tomography (μCT) enables non-destructive observations of fragmented samples. We had observed hollow-shaped single fibers using X-ray μCT, and determined aperture ratios, volumes, and local densities of the fibers. In this study, accuracies of the extracted aperture ratio and the volume have been discussed. The relationship between the coefficient of variation (CV, relative standard deviation) of extracted areas and the number of slices, N, was investigated. N of around 50 is statistically sufficient to determine aperture ratios and volumes of the fiber. Adjusting a threshold for binarization affects the CV of the aperture ratio, whereas the CV is within 2%. X-ray μCT enables to determine aperture ratios and volumes of the fibers with a high accuracy. An aperture ratio of a hollow-shaped single fiber is useful as one of the criteria for forensic examination. Observing a cross-sectional shape and determining a local density of a fragmented sample using X-ray μCT develop analysis of the sample including a single fiber. In addition, a procedure of CT-image analysis using the open source software “ImageJ Fiji” has been also presented in detail.

The handling of nuclear fuel materials is strictly restricted and, in principle, they cannot be taken out of the hood in an unsealed state. On the other hand, in the total reflection X-ray fluorescence analysis method, the depth of penetration of X-rays into a sample is extremely shallow, so the sample surface cannot be covered with a thin film or the like, and it is necessary to analyze the sample in an unsealed state. For this reason, total reflection analysis of nuclear fuel materials has rarely been performed. However, the establishment of a technique for analyzing nuclear fuel materials by total reflection X-ray fluorescence analysis, which is more sensitive than conventional XRF analysis, is expected to contribute to the rapid analysis of nuclear fuel materials at various facilities. In this study, a portable total-reflection X-ray fluorescence analyzer was installed in a hood to perform total-reflection X-ray fluorescence analysis of uranium, neptunium, and plutonium dropped on a glass substrate. Of these, uranium and plutonium are nuclear fuel materials. As a result of the measurement under strict control, clear U Lα, Np Lα, and Pu Lα peaks were observed in the total reflection X-ray fluorescence spectra, and their detection limits were 1.1, 1.1, and 1.3 ng, respectively.

To investigate cesium (Cs) distribution in tissues, high-energy synchrotron radiation X-ray fluorescence (SR-XRF) analysis with microprobe was applied to Cs imaging of mice renal specimens. Cs images were constructed using the intensity data of Cs Kα line (30.968 keV) at each point obtained by scanning the specimens with microbeam (1.0 μm×1.0 μm, 37 keV). The detection limit evaluated with thin section standards of Cs was 6 μg/g (counting time, 10 sec). Clear images of Cs corresponding to fine tissue structures were obtained from renal specimens of mice exposed to Cs (50 mg/kg, oral). Cs was found in the medulla and the outer strip of the outer medulla.

To clarify the σ* peak structures in C K-XANES of carbon materials and to analyze the structure of aggregated n-alkanes, C K-XANES spectra of various n-alkanes were measured in BL10/NewSUBARU, and the XANES profiles were theoretically analyzed by the first principles calculations. From the incident-angle-dependent C K-XANES, it can be found that n-C₃₆H₇₄ spin-coated on Au-substrate takes vertical-orientation but n-C₃₆H₇₄ pressed on In-substrate takes less orientation. It was also confirmed that the vertical-orientation of n-C₃₆H₇₄ on Au substrate reduced from solid state to melted state by heating. Considering the electric field vector directions on C K-XANES simulations by DFT calculations, the measured vertical-orientation of n-C₃₆H₇₄ can be well explained with the perpendicular conformations of alkane-chain-backbone to the substrate plane. MD calculations of n-C₃₆H₇₄ molecules on Au confirmed that aggregated n-C₃₆H₇₄ molecules partially take perpendicular conformations to the Au surface.

We investigated the photocatalysis of dendritic nanostructured WO₃/W composite materials fabricated by He plasma irradiation to tungsten plates, followed by the surface oxidation. The samples promoted the decolorization reaction of methylene blue (MB) aqueous solution under near infrared (NIR) light irradiation. To verify the MB molecule is actually decomposed by the photocatalysis of the samples, reaction products were analyzed by S K-edge XANES measurements for the MB solution kept with the samples under the light irradiation. By the light irradiation, the σ*(S-C) peak in the XANES spectra reduced and a new peak originated from SO₄²⁻ species was clearly observed, suggesting that S-C bonds in a MB molecule are broken by the NIR light irradiation and finally the sulfur species exists in the solution in the state of SO₄²⁻ ion. These results demonstrate that the photocatalytic decomposition of MB molecules really proceeds over WO₃/W composite materials even under NIR light irradiation.

Ag loaded Ga₂O₃ photocatalysts are well known to be highly active for the CO₂ reduction with water to CO. However, Ag changes its chemical state during the reaction, resulting in the decrease of its photocatalytic activity. We have attempted a real time observation of the change in the chemical and physical states of Ag co-catalyst loaded on Ga₂O₃ by monitoring UV-Vis diffuse reflectance spectra and Ag L₃-edge XANES spectra under the atmosphere simulating the photocatalytic CO₂ reduction. It was revealed that Ag initially loaded on Ga₂O₃ in the oxidized state was dissolved as Ag⁺ in water and precipitated as Ag-NPs. Then, some of Ag-NPs aggregated to be larger Ag particles or in the metallic state. Such dynamic process of Ag cocatalyst depends on gas species of the system, i.e. water promoted the formation of Ag-NPs while the adsorption of CO₂ on Ga₂O₃ and/or the oxidized Ag cocatalyst suppressed the formation of Ag-NPs.

Time-resolved Cl(2p), O(1s) XPS spectra of sodium perchlorate(NaClO₄), sodium chlorate(NaClO₃) and sodium chlorite(NaClO₂) were measured with a minimum measurement time of 15 minutes. For NaClO₄, Cl(Ⅶ) was reduced to Cl(−Ⅰ) via Cl(Ⅴ) by X-ray irradiation. For NaClO₃, Cl(Ⅴ) was similarly reduced to Cl(−Ⅰ) via Cl(Ⅲ) by X-ray irradiation. On the other hand, for NaClO₂, not only Cl(Ⅲ) is reduced to Cl(−Ⅰ) via Cl(Ⅰ), but also the disproportionation as 2 Cl(Ⅲ) → Cl(Ⅰ) + Cl(Ⅴ) was occurred. Simultaneously with each reduction in the solid state, the oxygen atoms bound to the chlorine atoms in the sample were oxidized to oxygen molecules by X-ray irradiation. Kinetic analysis was performed on these reactions to obtain the kinetic parameters of each reaction. The kinetic parameter of the reduction for NaClO₂ (Cl(Ⅲ) → Cl(Ⅰ)) showed the largest values.

Silicon is a promising anode material for lithium-ion secondary batteries (LIBs) due to its much higher gravimetric energy density compared to traditional graphite anodes, but its chemical degradation factors are largely unknown. Here we report the results of an X-ray absorption spectroscopy (XAS) study of the chemical reactivity between Si electrodes and electrolyte solutions, which leads to electrode degradation. A 50 nm-thick amorphous Si (a-Si) thin film electrode deposited by DC magnetron sputtering was prepared as a model Si electrode for XAS measurements. Si K-edge XAS spectra of a-Si thin film electrodes soaked in LiPF₆ electrolyte solutions show that the active material of the a-Si thin film electrode changes its chemical state from a-Si to hexafluorosilicate (Li₂SiF₆). It is clear that the Si electrode is degraded simply by contact with the LiPF₆ salt in the electrolyte solution, regardless of charging or discharging.

It is necessary to distinguish chemical forms of uranium coordinated with biological ligands and chelating agents in biological fluids when chelating ability of decorporation agents would be evaluated at internal exposure to actinides including uranium. X-ray Absorption Fine Structure (XAFS) has been applied to biological samples to confirm chemical forms of uranium, however, it has been difficult to identify their ligands coordinated to uranium because the differences in the XAFS spectra of them by the conventional method were too small. On the other hands, High Energy Resolution Fluorescence Detected X-ray Absorption Fine Structure (HERFD-XAFS) can be used to distinguish several kinds of ligands species because its extremely high S/B ratio makes XAFS spectra clearer to provide detailed information about the local structure. HERFD-XAFS measurement were performed at BL11XU, SPring-8, using undulator radiation so that beam damages to specimens and sample holders should be taken into account for safety use of uranium. In this study, rubidium was selected as a simulated element of uranium whose energy of Rb Kα line is close to that of U Lα₁ line, and HERFD-XAFS spectra of standard materials of rubidium such as Rb₂SO₄ and serum droplet samples were measured. X-ray Absorption Near Edge Structure, (XANES) spectra of 0.1 wt% Rb₂SO₄, RbCl, and RbBr in HERFD-XAFS showed clearer oscillation structure with high S/B ratio than those by the conventional fluorescence mode. HERFD-XAFS spectra of serum droplets in 1 μL containing rubidium also could be obtained, however, the polypropylene film on the sample holder was damaged through 1.5 h irradiation. The sealing materials of sample to avoid beam damage should be found to prepare for HERFD-XAFS measurement of uranium specimens.

Micro Energy-dispersive X-ray fluorescence spectroscopy (μED-XRF), one of the X-ray fluorescence spectroscopy (XRF), can analyze samples in a non-destructive and non-contact. It also has the advantage of being able to analyze small amount of samples.

In geoscience, it is required to analyze the elemental composition of the pumice generated at Fukutoku-Oka-no-Ba, which erupted in August 2021, and to estimate the source. The μED-XRF technique is utilized to analyze major element composition of pumices. Pumice is a volcanic rock consisting of highly vesicular volcanic glass due to rapid cooling of magma. Since its chemical compositions reflect magma composition and volcanoes produce erupted materials with characteristic chemical composition, specification of volcano source that erupted pumices may be possible by analyzing the elemental composition of pumices. Pumice stones originated from submarine eruption could be eroded as they drift for long time and become microscopic in size. The μED-XRF can be powerful tool for analysis of these pumices, as it can analyze small amounts of samples.

In this study, we investigated an analytical method that can measure pumice samples easily using μED-XRF. With improved method, we analyzed 37 pumice samples collected from coastal area in Japan and Thailand to identify whether pumices were originated from the Fukutoku Oka-no-Ba submarine volcano eruption in August 2021. Possible drifted patterns are also proposed.

A three-dimensional polarized optics energy-dispersive X-ray fluorescence spectrometer was used to analyze trace elements in blush color cosmetics. 14 elements (Mg, Al, Si, Cl, K, Ca, Ti, Fe, Zn, Rb, Sr, Sn, Ba, Pb) were rapidly detected by using five secondary target materials (Al, Ti, Ge, Mo, and Al₂O₃). Lead was detected only in a blush sample sold at inexpensive $1 stores. Six of the detected elements (Ti, Zn, Sr, Sn, Ba, and Pb) were tried to quantify by using calibration curves of the standard addition method with secondary target materials (Ge, Mo, and Al₂O₃). Since the matrix of blush color cosmetics is complex, containing minerals, oil components, surfactants, etc., it was effective to use the calibration curves of the standard addition method, which adds a certain amount of chemical reagents to blush color, instead of the absolute calibration curve method using standard materials prepared by mixing boron nitride and chemical reagents. As an example, in the $1 store blush color, Ti was calculated to be 1.5%, and Zn, Sr, Sn, Ba, and Pb were calculated to be 190 mg/kg, 23 mg/kg, 6.6 mg/kg, 1300 mg/kg, and 9.2 mg/kg, respectively.

Time-of-Flight (TOF) neutron diffraction measurements were carried out to observe the microstructure evolution during the bainitic transformation of the low-alloy TRIP (TRansformation Induced Plasticity) steels. Carbon is enriched in the austenite phase through the intercritical region where the austenite and ferrite phases coexist. To investigate the effect of intercritical temperatures on microstructure evolution during bainitic transformation, the changes in phase fractions of austenite and ferrite phases and carbon concentration in the austenite phase during bainitic transformation were investigated. Two conditions were used for the intercritical temperatures: 973 K and 1053 K. The shape changes of the 111 reflection of the austenite phase identified a low-carbon austenite phase and a high-carbon austenite phase during the bainitic transformation. The final attained phase fraction of the high-carbon austenite phase was found to be higher at 973 K than at 1053 K. Primary ferrite was formed in the intercritical regions, and the lower the intercritical temperature, the higher the amount of primary ferrite formed. Correspondingly, the carbon concentration of the austenite phase in the duplex region increased. As a result, the austenite phase was stabilized, which may have increased the fraction of the high-carbon austenite phase during bainitic transformation. We also developed an analytical scheme to determine the phase fraction from the diffraction intensity ratio of the strongest reflections of the austenite and ferrite phases, respectively. As a result, the phase fraction can be traced with a time step of one-fifth of the conventional time step, which makes it possible to trace phase transformation that occurs in tens of seconds at high temperatures.