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Takahashi, Yoshio*; Miura, Hikaru*; Yamada, Shinya*; Sekizawa, Oki*; Nitta, Kiyofumi*; Hashimoto, Tadashi*; Yomogida, Takumi; Yamaguchi, Akiko; Okada, Shinji*; Itai, Takaaki*; et al.
Journal of Hazardous Materials, 495, p.139031_1 - 139031_19, 2025/09
In this presentation, we analyzed the chemical state of cesium in radiocesium-bearing microparticles (CsMPs) released during the 2011 Fukushima Daiichi Nuclear Power Plant accident using high-resolution X-ray absorption spectroscopy (XANES) and micro X-ray fluorescence (
-XRF). The results identified two forms of cesium: one dissolved in glass and the other enriched on the surfaces of internal voids. The latter is considered to have originally existed as a gas and became concentrated during the cooling and solidification of the molten glass. These findings are crucial for understanding the formation process of CsMPs during the accident, as well as for future decommissioning and safety assessments.
Kobayashi, Hikaru*; Suto, Masahito*; Otsuki, Kentaro*; Yoshimura, Kazuya; Yoshida, Hiroko*
Japan Architectural Review (Internet), 6(1), p.e12353_1 - e12353_12, 2023/00
(001) surface using supersonic seeded oxygen molecular beamKatsube, Daiki*; Ono, Shinya*; Takayanagi, Shuhei*; Ojima, Shoki*; Maeda, Motoyasu*; Origuchi, Naoki*; Ogawa, Arata*; Ikeda, Natsuki*; Aoyagi, Yoshihide*; Kabutoya, Yuito*; et al.
Langmuir, 37(42), p.12313 - 12317, 2021/10
Times Cited Count：4 Percentile：18.65(Chemistry, Multidisciplinary)We investigated the oxidation of oxygen vacancies at the surface of anatase TiO(001) using supersonic seeded molecular beam (SSMB) of oxygen. The oxygen vacancies at the top-surface and sub-surface could be eliminated by the supply of oxygen using an SSMB. These results indicate that the interstitial vacancies can be mostly assigned to oxygen vacancies, which can be effectively eliminated by using an oxygen SSMB. Oxygen vacancies are present on the surface of anatase TiO(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the as-grown condition, could also be effectively eliminated using the oxygen SSMB.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：60 Percentile：95.95(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
decomposition on Si(110)Yano, Masahiro; Uozumi, Yuki*; Yasuda, Satoshi; Asaoka, Hidehito; Tsukada, Chie*; Yoshida, Hikaru*; Yoshigoe, Akitaka
e-Journal of Surface Science and Nanotechnology (Internet), 16, p.370 - 374, 2018/08
reduction reaction region at void periphery on Si(110)Yano, Masahiro; Uozumi, Yuki*; Yasuda, Satoshi; Tsukada, Chie*; Yoshida, Hikaru*; Yoshigoe, Akitaka; Asaoka, Hidehito
Japanese Journal of Applied Physics, 57(8S1), p.08NB13_1 - 08NB13_4, 2018/07
Times Cited Count：2 Percentile：7.77(Physics, Applied)Yokobori, Shinichi*; Kawaguchi, Yuko*; Harada, Miyu*; Murano, Yuka*; Tomita, Kaori*; Hayashi, Nobuhiro*; Tabata, Makoto*; Kawai, Hideyuki*; Okudaira, Kyoko*; Imai, Eiichi*; et al.
no journal, ,
no abstracts in English
Cl on Si(100)2
1 by means of SR-XPSTsukada, Chie; Yoshida, Hikaru; Okada, Michio*; Yoshigoe, Akitaka; Yaita, Tsuyoshi
no journal, ,
Cs in clay mineral will be easy to desorb as halide. We should investigate the desorption mechanism. The clay mineral is constructed mainly by oxide with Si and Al. Thus, Si substrate and CH
Cl are selected as the reaction model materials. The final purpose is to reveal the reaction for CHCl molecular beam on Cs/Si substrate by means of XPS with synchrotron radiation (SR-XPS). As the first step, the purpose in this study is to reveal the adsorption reaction for CHCl molecular beam on Si(100)21 by means of SR-XPS. The CHCl will adsorb at CH and/or Cl group on the Si dimer atom, respectively.
Kobayashi, Kensei*; Kawamoto, Yukinori*; Sarker, P. K.*; Kuwahara, Hideharu*; Obayashi, Yumiko*; Kaneko, Takeo*; Mita, Hajime*; Yabuta, Hikaru*; Yoshida, Satoshi*; Narumi, Issei; et al.
no journal, ,
no abstracts in English
Tsukada, Chie*; Yoshida, Hikaru; Ogawa, Satoshi*; Yoshigoe, Akitaka; Yagi, Shinya*; Yaita, Tsuyoshi
no journal, ,
To recovery from the Fukushima Daiichi Nuclear Power Station accident, the removal of radioactive Cs from the soil and cooling water is important. An absorbent and a removal procedure of Cs are required to have properties of effective separation ability, recyclable and energy saving. Here, we focus on the gold nanoparticles (AuNPs) fabricated by solution plasma method. The purpose of this study is to reveal the surface chemical states of the AuNPs fabricated by solution plasma method in CsCl aqueous solution. From the synchrotron light based analysis, it was found that the Cs-Cl-Au bondings form by the repeat of below two steps. (1) Cs and Cl atoms adsorb on AuNPs surface (Cs-Au and Cl-Au bondings). (2) Au atoms bonds around the AuNPs surface.
Chen, B.*; Yoshida, Takehito*; Yokomura, Ryota*; Terashima, Hikaru*; Hanari, Toshihide; Kawabata, Kuniaki; Fukui, Rui*
no journal, ,
In the decommissioning of Fukushima Daiichi Nuclear Power Station, the modularized rail structure, "Rail DRAGON" has been developed to observe inside the PCV for avoiding the troubles of robot teleoperation. Because there are obstacles on the path of the extending rail, the operators need to control the joint angles and avoid them. In this research, we propose "wire switch method" to concurrently execute the module connection and the control of joint angles. By setting up a detour of the power line and automatically judging the suitable moment that the fluctuation of angle signals is small, we proved that joint control can be maintained during the wire switching.
Tsukada, Chie; Yoshida, Hikaru; Ogawa, Satoshi*; Yoshigoe, Akitaka; Yagi, Shinya*; Yaita, Tsuyoshi
no journal, ,
We focus on the Au nanoparticle, which is fabricated by solution plasma method, as the adsorbent with high density and high efficiency of Cs
in solution. To remove the Cs from the solution, we attempt two methods, which are the Cs adsorption on the Au nanoparticle surface and the interaction between the Cs and the L-cysteine on Au nanoparticle. Judging from the results of SR-XPS for the sample at the latter method, we suggest the interaction between the Cs and the COOH group of L-cysteine on Au nanoparticle.
Yokobori, Shinichi*; Kawaguchi, Yuko*; Shimizu, Yasuyuki*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Sugino, Tomohiro*; Takahashi, Yuta*; Yang, Y.*; Tanigawa, Yoshiaki*; Hashimoto, Hirofumi*; et al.
no journal, ,
no abstracts in English
Tsukada, Chie*; Yoshida, Hikaru; Ogawa, Satoshi*; Yoshigoe, Akitaka; Yagi, Shinya*; Yaita, Tsuyoshi
no journal, ,
The decontamination of radioactive Cs from the soil and the water has been required in Fukushima. Gold nanoparticles (AuNPs) are attractive candidate for Cs adsorbent. AuNPs fabricated by solution plasma method is not covered by dispersant and is almost clean. It is known that L-cysteine rapidly adsorbs and exists with high density on the AuNPs surface. The electrostatic attractive force may be useful to induce interactions between -COO- of L-cysteine and Cs ion in aqueous solution. This study reveals the adsorption reaction between the Cs and the Cys/AuNP. Cys/AuNP has a peak and CsCl/Cys/AuNP has no peak in Na 1s spectra. Cys/AuNP has no peak and CsCl/Cys/AuNP has a peak for Cs 3
spectra. From these results, Na on Cys/AuNP is replaced by Cs after reaction in CsCl aqueous solution. Cys/AuNP and CsCl/Cys/AuNP have a O 1s peak, where the peak position of CsCl/Cys/AuNP is higher than that ofCys/AuNP. This indicates the further polarization of -COO- by replacing Na by Cs.
-ray directional radiation dose detector with good efficiency for field surveyYamamori, Ryo*; Kobayashi, Hikaru*; Honta, Shohei*; Yoshino, Hiroshi*; Nozaki, Atsuo*; Ichijo, Yusuke*; Hijikata, Yoshio*; Yoshida, Hiroko*; Furuta, Takuya
no journal, ,
Understanding radiation field is important to predict radiation dose rate in newly constructing buildings in an area widely contaminated by radioactive nuclei. Directional spectra of the radiations are important to consider the shielding effect of the building. We adopts a method to measure the directional spectra by adopting a plate of lead collimator in front of the scintillator and subtract the values from the spectra measured without lead collimator. We investigated a possible weight saving detection system having sufficient detection efficiency. The investigation was carried out for the condition of the collimator radius (
= 10, 15, 20 cm) and the distance between collimator and detector (
= 1, 3, 5 cm). We found that three combinations satisfied the 90 field view and the detection efficiency became better with larger collimator radius. On the other hand, larger collimator radius indicate heavier detection system. Therefore, we developed an optimum detection system for field survey with the 15 cm diameter plate (10kg), the scintillator (3.4kg), and the folder (1.0kg).
Kobayashi, Kensei*; Kawamoto, Yukinori*; Sarker, P. K.*; Ono, Keisuke*; Kuwahara, Hideharu*; Obayashi, Yumiko*; Kaneko, Takeo*; Mita, Hajime*; Yabuta, Hikaru*; Yoshida, Satoshi*; et al.
no journal, ,
H
on Cu(410)Makino, Takamasa*; Tsuda, Yasutaka*; Yoshida, Hikaru; Yoshigoe, Akitaka; Okada, Michio*
no journal, ,
The de-hydrogenation reaction of hydrocarbon molecules at metal surface is important as an elementary process of graphene generation and various catalytic reactions. In order to investigate CH reactions at Cu(410) surface, CH molecular beams and synchrotron radiation X-rays photoelectron spectroscopy was used. We found that the chemical species which became dehydrogenation adsorbs at the surface when CH molecule has kinetic energy of 2 eV.
Pt(111)Tsuda, Yasutaka*; Makino, Takamasa*; Yoshida, Hikaru; Yoshigoe, Akitaka; Fukuyama, Tetsuya*; Okada, Michio*
no journal, ,
The oxidation with oxygen molecules is important in a metal corrosion process. In order to develop high noncorrosive materials, the understanding of oxidation processes is significant. In this study, the influence on oxidation reaction due to alloy ingredient difference was investigated by the comparison between CuAu(111) and CuPt(111) surfaces. It was found that the CuPt(111) surface has lower reactivity than the CuAu(111) surface.
Ajikawa, Yusuke*; Yamamoto, Yukio*; Yoshida, Hikaru; Yoshigoe, Akitaka
no journal, ,
A very small amount of gas control was indispensable for surface reaction experiments under ultrahigh vacuum conditions. Normally, it has been performed with a variable leak valve by the manual operation. However, the manual operation can not apply for advanced experiments such as multi-measurements. The automatic precise valve control would lead to the burden reduction and reproducible improvement. The antomatic control also has a metrit to avid the loss of control for the apparatus. In this conference, we will report recent developments of the automatic pressure control system and some results of precise pressure control from 10
to 10
Pa.
Cl on Si(100)21 by means of SR-XPSTsukada, Chie; Yoshida, Hikaru; Okada, Michio*; Yoshigoe, Akitaka; Yaita, Tsuyoshi
no journal, ,
To achieve Cs decontamination in clay minerals by using CHCl gas, we have investigated the adsorption reactions and adsorption states of CHCl at Si surfaces. In this conference, we report that dissociative adsorption of CHCl to form CH and Cl was revealed from the high energy-resolutions photoemission spectra.
