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Osawa, Takahito
Materia, 64(3), p.153 - 156, 2025/03
In order to obtain accurate information on the elemental composition in a sample, it is very important to select an appropriate analytical method, and it is necessary to have a correct understanding of the advantages and disadvantages of each analytical method. This paper introduces prompt gamma-ray analysis as an unusual method that is different from elemental analysis methods that readers may be familiar with, and explains what makes it different from well-known analysis methods. The research on cultural properties conducted with the prompt gamma-ray analysis system (PGA) and future developments will also be described.
Ebihara, Mitsuru*; Shirai, Naoki*; Osawa, Takahito; Yamaguchi, Akira*
Geochimica et Cosmochimica Acta, 389, p.200 - 210, 2025/01
Times Cited Count：0 Percentile：0.00(Geochemistry & Geophysics)The 15 elements including most major elements of 12 carbonaceous chondrites collected in Antarctica were quantified using neutron-induced prompt gamma-ray analysis. While some of these samples were observed to share affinities with CI or CM chondrites, they do not exhibit the same characteristics as the known CI or CM chondrites. As a result, a new group named "CY" has been proposed for these meteorites. Common among the 12 meteorites is the depletion of volatile elements H and chlorine, showing a correlation and being depleted compared to non-Antarctic CI levels. Based on the abundance of moderately volatile elements Mn and S, the 12 meteorites can be divided into two groups: one with levels similar to non-Antarctic CI and the other with intermediate levels between CI and CM. These results suggest that CY chondrites originate from distinct parent bodies (materials), and considering two different parent bodies (materials) is necessary.
Sumita, Takehiro*; Osawa, Takahito; Chiu, I.-H.; Ikeda, Atsushi
Analytica Chimica Acta, 1329, p.343256_1 - 343256_10, 2024/11
Times Cited Count：1 Percentile：0.00(Chemistry, Analytical)Osawa, Takahito
Bunseki (Internet), (11), p.428 - 434, 2024/11
Methods for fully automating complex wet chemistry operations will be described, using examples of laboratory automation systems that the author has developed.
Osawa, Takahito
Chikyu Kagaku, 58(3), p.70 - 82, 2024/09
This paper describes the recent research and development status of neutron-induced prompt gamma-ray analysis and muonic X-ray analysis as elemental analysis methods using quantum beams. Neutron-induced prompt gamma-ray analysis is an elemental analysis method using neutrons, and is often used as a nondestructive quantitative analysis method for boron and hydrogen. The prompt gamma-ray analysis system (PGA) installed at JRR-3 is an old device constructed more than 30 years ago, but recently an articulated robot has been installed and an advanced automated analysis system is in operation. On the other hand, the muonic X-ray analysis method is attracting attention as a new analysis method, and can detect light elements such as oxygen nondestructively. Both analytical methods have been used in the analysis of the samples of asteroid Ryugu, and will continue to evolve greatly as analytical methods in the future.
Ninomiya, Kazuhiko*; Osawa, Takahito; Terada, Kentaro*; Wada, Taiga*; Nagasawa, Shunsaku*; Chiu, I.-H.; Nakamura, Tomoki*; 40 of others*
Meteoritics & Planetary Science, 59(8), p.2044 - 2057, 2024/08
Times Cited Count：1 Percentile：58.96(Geochemistry & Geophysics)Samples from asteroid Ryugu, brought back by asteroid explorer Hayabusa2 are important for investigating the origin and evolution of the solar system. Here, we report the elemental compositions of a 123 mg Ryugu sample determined with a nondestructive muon elemental analysis method. This method is a powerful tool for determining bulk chemical composition, including light elements such as C, N, and O. From the muonic X-ray spectra with three carbonaceous chondrites, the relationship between the elemental composition and muonic X-ray intensity was determined for each element. Calibration curves showed linearity, and the elemental composition of Ryugu was quantitatively determined. The results reflect the average bulk elemental composition of asteroid Ryugu owing to the large amount of samples. Ryugu has an elemental composition similar to that of Orgueil (CI1), and should be classified as CI1. However, the O/Si ratio of Ryugu is 25% lower than that of Orgueil, indicating that Orgueil may have been seriously contaminated by terrestrial materials after its fall to Earth. These results indicate that the Ryugu sample is more representative than the CI chondrites as a solid material of the solar system.
Kim, J.*; Thompson, B. R.*; Tominaga, Taiki*; Osawa, Takahito; Egami, Takeshi*; F
rster, S.*; Ohl, M.*; Senses, E.*; Faraone, A.*; Wagner, N. J.*
ACS Macro Letters (Internet), 13(6), p.720 - 725, 2024/06
Times Cited Count：1 Percentile：47.49(Polymer Science)The Rouse dynamics of polymer chains in model nanocomposite PolyEthylene Oxide (PEO)/Silica NanoParticles (NPs) was investigated using QuasiElastic Neutron Scattering (QENS). The apparent Rouse rate of the polymer chains decreases as the particle loading increases. However, there is no evidence of an immobile segment population on the probed time scale of tens of ps. The slowing down of the dynamics is interpreted in terms of modified Rouse models for the chains in the NP inter-phase region. Thus, two chain populations, one bulk like and the other characterized by a suppression of Rouse modes, are identified. The spatial extent of the interphase region is estimated to be about twice the adsorbed layer thickness, or about 2 nm. These findings provide a detailed description of the suppression of the chain dynamics on the surface of NPs. These results are relevant insights on surface effects and confinement and provide a foundation for the understanding of the rheological properties of Polymer NanoComposites (PNCs) with well-dispersed NPs.
Terada, Kentaro*; Ninomiya, Kazuhiko*; Sato, Akira*; Tomono, Dai*; Kawashima, Yoshitaka*; Inagaki, Makoto*; Nambu, Akihiro*; Kudo, Takuto*; Osawa, Takahito; Kubo, Kenya*
Journal of Analytical Science and Technology, 15, p.28_1 - 28_7, 2024/05
Times Cited Count：1 Percentile：52.96(Chemistry, Analytical)In Earth and planetary science, Pb isotopic composition is well known to play a key role in deciphering the origin and evolution of materials because they provide unique chronological and/or indigenous regional information as a radiogenic daughter nuclide from U and Th. To determine such an isotopic composition, a mass spectrometer has been widely used over several decades, which requires a destructive treatment such as laser ablation and thermal ionization, so on. Here we first report the non-destructive Pb isotopic measurement of the natural galena (PbS) using an energy-shift of muon-induced characteristic X-rays. The observed Pb isotopic composition of the natural galena is in good agreement with that obtained by conventional mass spectrometry.
Osawa, Takahito
Kenkyu Kaihatsu Reda, 20(8), p.7 - 11, 2023/11
This review outlines technical methodologies for automating labor-intensive experiments, especially wet separation experiments.
Matsuoka, Moe*; Kagawa, Eiichi*; Amano, Kana*; Nakamura, Tomoki*; Tatsumi, Eri*; Osawa, Takahito; 51 of others*
Communications Earth & Environment (Internet), 4, p.335_1 - 335_12, 2023/09
Times Cited Count：11 Percentile：88.30(Environmental Sciences)Visible and near-infrared (Vis-NIR) spectra of returned samples from Cb-type asteroid (162173) Ryugu exhibit very low reflectance values and absorptions that are generally consistent with observations from the Hayabusa2 ONC-T and NIRS3 instruments. A notable difference is that a metal-OH absorption at 2.72 misrometer is more than twice as deep in laboratory sample spectra compared with those of Ryugu's surface. Based on the laboratory experiments to investigate the range of spectral variation by physical properties and space weathering, we conclude that the spectral differences between returned samples and asteroid surface are best explained by a combination of (1) porosity, (2) particle size, and (3) degree of space weathering effects, with the latter being the most effective. Those effects can explain spectral variations between Cb-type asteroids, suggesting that these asteroids consist of the same CI-chondrite material with different physical properties and weathering degrees. Extremely homogeneous Vis-NIR spectra of the entire Ryugu surface in comparison with the heterogeneous spectra of a near-Earth S-type asteroid (25143) Itokawa indicate that the space weathering has been processing more rapidly on Cb-type asteroids compared with S-type asteroids. Because the major component of Cb-type asteroids are porous hydrous silicates that have lower melting temperature and lower material strength than anhydrous silicates, the surface of Cb-type asteroids are more susceptible to the alteration by impacts of interplanetary dust particles.
Chiu, I.-H.; Terada, Kentaro*; Osawa, Takahito; Park, C.*; Takeshita, Soshi*; Miyake, Yasuhiro*; Ninomiya, Kazuhiko*
Meteoritics & Planetary Science, 58(9), p.1333 - 1344, 2023/09
Times Cited Count：0 Percentile：0.00(Geochemistry & Geophysics)Osawa, Takahito
Shiki, 59, p.4 - 7, 2023/06
Elemental analysis using negative muons has made remarkable progress as a result of the research and development for the application of muons to the analysis of samples brought back to earth by the Hayabusa-2. This paper describes the analysis of Ryugu samples at J-PARC, from the development of the instrument to the analysis results.
Osawa, Takahito
Keisoku Gijutsu, 51(6), p.21 - 26, 2023/05
Decompression filtration is a common operation in wet chemistry, and the method using a filtration bell is often used. The author has been developing a fully automated system for wet separation operations, and has developed an automatic decompression filtration device exclusively for robots. In addition, the specifications of this device were changed so that it can be operated by human operators, and it was commercialized.
Osawa, Takahito; Nagasawa, Shunsaku*; Ninomiya, Kazuhiko*; Takahashi, Tadayuki*; Nakamura, Tomoki*; Wada, Taiga*; Taniguchi, Akihiro*; Umegaki, Izumi*; Kubo, Kenya*; Terada, Kentaro*; et al.
ACS Earth and Space Chemistry (Internet), 7(4), p.699 - 711, 2023/04
Times Cited Count：6 Percentile：76.87(Chemistry, Multidisciplinary)The concentrations of carbon and other major elements in asteroid samples provide very important information on the birth of life on the Earth and the solar-system evolution. Elemental analysis using muonic X-rays is one of the best analytical methods to determine the elemental composition of solid materials, and notably, is the only method to determine the concentration of light elements in bulk samples in a non-destructive manner. We developed a new analysis system using muonic X-rays to measure the concentrations of carbon and other major elements in precious and expectedly tiny samples recovered from the asteroid Ryugu by spacecraft Hayabusa2. Here we report the development process of the system in 4 stages and their system configurations, The analysis system is composed of a stainless-steel analysis chamber, an acrylic glove box for manipulating asteroid samples in a clean environment, and Ge semiconductor detectors arranged to surround the analysis chamber. The performance of the analysis system, including the background level, which is crucial for the measurement, was greatly improved from the first stage to the later ones. Our feasibility study showed that the latest model of our muonic X-ray analysis system is capable of determining the carbon concentration in Hayabusa2's sample model with an uncertainty of less than 10 percent in a 6-day measurement.
Osawa, Takahito
Hoshaka Bunseki, (34), p.34 - 50, 2023/04
This paper describes the nomenclature, principles, advantages and disadvantages of prompt gamma-ray analysis, the configuration of the PGA installed in JRR-3, what kind of analysis can be performed with the PGA, and how to use the PGA, respectively.
Chiu, I.-H.; Terada, Kentaro*; Osawa, Takahito; Park, C.*; Takeshita, Soshi*; Miyake, Yasuhiro*; Ninomiya, Kazuhiko*
Journal of Physics; Conference Series, 2462, p.012004_1 - 012004_6, 2023/03
Times Cited Count：1 Percentile：73.99(Physics, Applied)In the last decade, non-destructive elemental analysis using negative muon beams advanced significantly. This method can be used to determine the elemental composition of bulk materials without causing damage. In this study, we performed a negative muon irradiation experiment for a Northwest Africa 482 lunar meteorite (NWA482), which was installed in a stainless steel analysis chamber. The analysis chamber was filled with helium gas to suppress the background signals caused by air-scattering muons. The muonic X-rays from Al, Fe, Ca, Mg, Si, and O in the samples were detected using six high-purity germanium semiconductor detectors arranged around the analysis chamber. To correct the X-ray self-absorption effect of the samples, a Monte-Carlo simulation using Geant4 toolkit was used. Based on the quantitative analysis for muonic X-ray measurement with the correction application from the simulation, we successfully investigated the analytical sensitivity of each element in meteorites based on the NWA482 data.
Nakamura, Tomoki*; Osawa, Takahito; 219 of others*
Science, 379(6634), p.eabn8671_1 - eabn8671_14, 2023/02
Times Cited Count：181 Percentile：99.98(Multidisciplinary Sciences)Mineralogical, petrological, and physical properties of sixteen Ryugu particles measuring 1-8 mm indicate that they are most similar to CI chondrites. The presence of CO
-bearing water in pyrrhotite indicates that the original parent asteroid formed beyond the HO and CO snow lines in the solar nebula, where, based on Ryugu mineralogy, very limited amounts of high-temperature objects including small chondrules and Ca, Al-rich inclusions were present. Fluid-rock reactions occurred at low-temperature, high pH, and reducing conditions at water/rock mass ratios smaller than 1 and changed an olivine-pyroxene rich lithology, remaining as the least-altered fragments in Ryugu samples, into phyllosilicate-carbonate rich lithologies, the predominant material of Ryugu samples. The solar nebula might have been still present when magnetite crystallized from the fluid in Ryugu's parent body.
Kobayashi, Takane*; Onishi, Tsuyoshi*; Osawa, Takahito; Pratt, A.*; Tear, S.*; Shimoda, Susumu*; Baba, Hidetada*; Laitinen, M.*; Sajavaara, T.*
Small, 18(46), p.2204455_1 - 2204455_9, 2022/11
Times Cited Count：10 Percentile：69.94(Chemistry, Multidisciplinary)An all-solid-state battery is a secondary battery that is charged and discharged by the transport of lithium ions between positive and negative electrodes. To fully realize the significant benefits of this battery technology, for example, higher energy densities, faster charging times, safer operation, it will be essential to understand how lithium ions are transported and distributed in the battery during operation. However, as the third lightest element, methods for quantitatively analyzing lithium during operation of an all-solid-state device are limited such that real time tracking of lithium transport has not yet been demonstrated. Here, we report that the transport of lithium ions in an all-solid-state half-cell was quantitatively tracked in near real time by utilizing a thermal neutron-induced nuclear reaction, utilizing lithium-6 as a tracer, and utilizing a high-intensity thermal neutron source. Furthermore, it is also mentioned that the migration mechanism and migration region of lithium ions in the solid electrolyte used could be determined by tracking the transport of lithium ions. From these results, it can be said that the development of all-solid-state batteries has entered a phase where further advances could be carried out while understanding the transport of lithium ions in the batteries. As a result, the research and development of all-solid-state batteries would be further accelerated.
Barucci, M. A.*; Reess, J.-M.*; Bernardi, P.*; Doressoundiram, A.*; Fornasier, S.*; Le Du, M.*; Iwata, Takahiro*; Nakagawa, Hiromu*; Nakamura, Tomoki*; Andr
, Y.*; et al.
Earth, Planets and Space (Internet), 73(1), p.211_1 - 211_28, 2021/12
Times Cited Count：21 Percentile：81.33(Geosciences, Multidisciplinary)The MMX InfraRed Spectrometer (MIRS) is an imaging spectrometer on board of MMX JAXA mission. MIRS is built at LESIA-Paris Observatory in collaboration with four other French laboratories, collaboration and financial support of CNES and close collaboration with JAXA and MELCO. The instrument is designed to fully accomplish MMX's scientific and measurement objectives. MIRS will remotely provide near-infrared spectral maps of Phobos and Deimos containing compositional diagnostic spectral features that will be used to analyze the surface composition and to support the sampling site selection. MIRS will also study Mars atmosphere, in particular to spatial and temporal changes such as clouds, dust and water vapor.
Osawa, Takahito
Hamon, 31(3), p.117 - 120, 2021/08
Muonic X-ray analysis is an elemental analysis method by detecting characteristic X-rays emitted from muonic atoms and has various advantages, for example, it can detect light elements such as carbon non-destructively. Our research group has been studying to apply this new analytical method to the sample of the asteroid Ryugu brought back by the asteroid explorer Hayabusa2. This paper outlines the research conducted at J-PARC muon facility so far and the preparation status of the experiment on Ryugu samples scheduled to be conducted from June to July 2021. To make this experiment successful, a device with a glove box has been developed that can analyze microsamples in a helium atmosphere, achieving very low background levels.
