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Journal Articles

Evaluation of doped potassium concentrations in stacked two-Layer graphene using real-time XPS

Ogawa, Shuichi*; Tsuda, Yasutaka; Sakamoto, Tetsuya*; Okigawa, Yuki*; Masuzawa, Tomoaki*; Yoshigoe, Akitaka; Abukawa, Tadashi*; Yamada, Takatoshi*

Applied Surface Science, 605, p.154748_1 - 154748_6, 2022/12

https://doi.org/10.1016/j.apsusc.2022.154748

Times Cited Count：3 Percentile：48.5(Chemistry, Physical)

Immersion of graphene in KOH solution improves its mobility on SiO $_{2}$ /Si wafers. This is thought to be due to electron doping by modification with K atoms, but the K atom concentration C $_{K}$ in the graphene has not been clarified yet. In this study, the C $_{K}$ was determined by XPS analysis using high-brilliance synchrotron radiation. The time evolution of C $_{K}$ was determined by real-time observation, and the C $_{K}$ before irradiation of synchrotron radiation was estimated to be 0.94%. The C 1s spectrum shifted to the low binding energy side with the desorption of K atoms. This indicates that the electron doping concentration into graphene is decreasing, and it is experimentally confirmed that K atoms inject electrons into graphene.

JAEA Reports

Development of technologies for enhanced analysis accuracy of fuel debris; Summary results of the 2020 fiscal year (Subsidy program for the project of decommissioning and contaminated water management)

Ikeuchi, Hirotomo; Koyama, Shinichi; Osaka, Masahiko; Takano, Masahide; Nakamura, Satoshi; Onozawa, Atsushi; Sasaki, Shinji; Onishi, Takashi; Maeda, Koji; Kirishima, Akira*; et al.

JAEA-Technology 2022-021, 224 Pages, 2022/10

JAEA-Technology-2022-021.pdf:12.32MB

A set of technology, including acid dissolving, has to be established for the analysis of content of elements/nuclides in the fuel debris samples. In this project, a blind test was performed for the purpose of clarifying the current level of analytical accuracy and establishing the alternative methods in case that the insoluble residue remains. Overall composition of the simulated fuel debris (homogenized powder having a specific composition) were quantitatively determined in the four analytical institutions in Japan by using their own dissolving and analytical techniques. The merit and drawback for each technique were then evaluated, based on which a tentative flow of the analyses of fuel debris was constructed.

JAEA Reports

Analytical method for chemical compositions of volcanic glasses in Tono Geoscience Center; Quantitative measurements of Major Elements by using EPMA and Minor Elements by LA-ICP-MS

Kagami, Saya; Yokoyama, Tatsunori; Umeda, Koji*

JAEA-Testing 2021-001, 49 Pages, 2021/08

JAEA-Testing-2021-001.pdf:3.86MB

To make a contribution to safety assessment for geological disposal of high level radioactive and/or TRU waste, we need to assess long-term stability of geological environment and predict long-term changes of geotectonic events that will occur in the future, especially for Quaternary period ( 2.6 million years ago-present). In the most case, we investigate chronological data of geological events by radiometric dating. When some geological samples have no objects to which radiometric dating method can be applied (e.g., zircon, biotite, wood fragments and plant residues), we can use tephrochronology, which is geological dating method using each layer of tephra (erupted volcanic ash), for dating of geological layers. This chronological method is essential in Japan, where volcanism is very active. Tephra is usually characterized by petrographic characteristics and/or chemical composition (mainly major elements) of volcanic glasses and/or minerals in tephra. In Tono Geoscience Center (Japan Atomic Energy Agency), we develop an analytical technique of chemical composition including trace elements of volcanic glasses for detailed tephra identification. In this paper, we report a sample preparation procedure and analytical methods of chemical compositions of individual volcanic glass shards by using an electron probe microanalyzer and a laser ablation-inductively coupled plasma-mass spectrometer.

Journal Articles

Determination of humic substances in deep groundwater from sedimentary formations by the carbon concentration-based DAX-8 resin isolation technique

Terashima, Motoki; Endo, Takashi*; Miyakawa, Kazuya

Journal of Nuclear Science and Technology, 57(4), p.380 - 387, 2020/04

https://doi.org/10.1080/00223131.2019.1688730

Times Cited Count：2 Percentile：21.58(Nuclear Science & Technology)

Journal Articles

A Spectroscopic technique for analysis developed in the field of unclear energy

Kusaka, Ryoji

Bunko Kenkyu, 67(6), p.239 - 240, 2018/12

A spectroscopic technique for analysis developed by collaboration between Japan Atomic Energy Agency (JAEA) and Quantum and Radiological Science and Technology (QST) is discussed for readers outside the field of nuclear energy. This paper introduces a quantitative analysis for $^{107}$ Pd radioisotope contained in a spent nuclear fuel by using laser-induced photoreduction and inductively coupled plasma mass spectrometry (ICP-MS). The importance and problems of quantitative analysis for radioisotopes in spent nuclear fuels are described, and the principle, advantages, and future applications of the spectroscopic technique are discussed.

JAEA Reports

A study on long term stability of bentonite; The preliminary study on the bentonite stability in the groundwater influenced by cementitious material

*; Mihara, Morihiro;

JNC TN8430 2001-007, 56 Pages, 2002/01

JNC-TN8430-2001-007.pdf:13.13MB

In the geological disposal concept of radioactive wastes, a kind of clay with sorption ability and low permeability, called bentonite, is envisaged as an engineered barrier system in the geological repository. Also, the cemetitious material is envisaged as the backfill material in the vaults and the structure material of the vaults. The groundwater in contact with the cementitious material will promote hyperalkaline conditions in the repository environment and these conditions will affect the performance of the bentonite. Therefore, it is necessary to investigate the interaction between the cementitious material and the bentonite for the evaluation of long term stability of the disposal system. In this study, for the identification and the investigation of the secondary minerals, the batch immersion experiments of the powder bentonite were carried out using synthetic cement leachates (pH=7, 12.5, 14) at 200 $^{circ}$ C. As the results, it was confirmed that Na as exchangeable cations in the bentonite can exchange relatively easily with Ca in the solution from the experiment results. And the ratio of cation exchange was estimated to be about 25% based on the amount of exchangeable cations Ca $^{2+}$ between layers. Furthermore, it was concretely shown that the generation of analcime might be affected by the Na concentration from results of the solution analyses and a stability analysis of analcime using the chemical equilibrium model, in addition to the pH in the solution.

Journal Articles

JAERI Takasaki in-air micro-PIXE system for various applications

Sakai, Takuro; Kamiya, Tomihiro; Oikawa, Masakazu*; Sato, Takahiro; Tanaka, Akira*; Ishii, Keizo*

Nuclear Instruments and Methods in Physics Research B, 190(1-4), p.271 - 275, 2001/09

https://doi.org/10.1016/S0168-583X(02)00469-X

Times Cited Count：66 Percentile：95.98(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Development of analytical techniques for ultra trace amounts of nuclear materials in environmental samples using ICP-MS for safeguards

Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Miyamoto, Yutaka; Yasuda, Kenichiro; Watanabe, Kazuo; Usuda, Shigekazu; Nishimura, Hideo; Adachi, Takeo

Applied Radiation and Isotopes, 53(1-2), p.87 - 90, 2000/07

https://doi.org/10.1016/S0969-8043(00)00117-2

Times Cited Count：28 Percentile：84.32(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Development of environmental sample analysis techniques for safeguards and its current status

Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Miyamoto, Yutaka; Yasuda, Kenichiro; Tsuruta, Yasuhiro; Tsuda, Shinji; Watanabe, Kazuo; Usuda, Shigekazu; Nishimura, Hideo; et al.

Kaku Busshitsu Kanri Gakkai Nihon Shibu Dai-20-Kai Kinen Taikai Rombunshu, p.183 - 187, 1999/11

no abstracts in English

JAEA Reports