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佐藤 優樹; 角藤 壮*; 田中 孝幸*; 嶋野 寛之*
European Physical Journal; Special Topics, 10 Pages, 2025/00
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)In decommissioning the Fukushima Daiichi Nuclear Power Station, understanding the distribution of radioactive substances is crucial to developing detailed decontamination plans and minimizing worker exposure. In this study, an autonomous mobile radiation source detection system based on a mecanum wheel robot equipped with a Compton camera was constructed. The Compton camera visualizes the radiation source, and software embedded in the robot system reads the results to recognize the radiation source and move the robot toward it. If the robot's depth camera detects an obstacle while moving, it changes direction, visualizes the radiation source again using the Compton camera, and repeats moving the robot toward the radiation source. Furthermore, two demonstration tests were conducted in the laboratory using a 
Cs radiation source to confirm that the robot can reach it where there are obstacles or a narrow region. We have also summarized issues that must be identified to apply this system to actual decommissioning sites.
Vu, TheDang*; 宍戸 寛明*; 相澤 一也; 奥 隆之; 及川 健一; 原田 正英; 小嶋 健児*; 宮嶋 茂之*; 曽山 和彦; 小山 富男*; et al.
IEEJ Transactions on Electrical and Electronic Engineering, 19(11), p.1888 - 1894, 2024/11
被引用回数：0 パーセンタイル：0.00(Engineering, Electrical & Electronic)We proposed a novel superconducting detector called the current-biased kinetic inductance detector (CB-KID) for constructing a neutron transmission imager. We systematically studied the characteristics of the CB-KID to improve spatial resolution down to 10 
m in transmission imaging. By analyzing neutron transmission spectra from 1 meV to 500 keV, we identified copper (Cu) and iron (Fe) as major components in commercial nuts and screws. Additionally, we successfully mapped the distribution of the SmSn
compound using selective energy regions of pulsed neutrons and the CB-KID detector. It can reveal transmission spectra across a wide range of energies, from cold-neutron energies (meV) to higher neutron energies (up to 500 keV).
Vu, TheDang*; 宍戸 寛明*; 相澤 一也; 奥 隆之; 及川 健一; 原田 正英; 小嶋 健児*; 宮嶋 茂之*; 曽山 和彦; 小山 富男*; et al.
Journal of Physics; Conference Series, 2776, p.012009_1 - 012009_9, 2024/06
We optimized the design and operating conditions of our superconducting neutron detector to improve spatial resolution. We obtained the best spatial resolution of 10 m when a Gd Siemens star pattern was mounted at close contact with the detector in the cryostat. We compared the effect of a different sample-detector distance on a spatial resolution when the samples were placed either at cryogenic temperature or at room temperature. We found the appearance of clear Bragg dips by the measurements of natural FeS
single crystals and succeeded in mapping the distribution of differently-oriented crystals by choosing several Bragg dips of the FeS crystals to compose the transmission images.
佐藤 優樹; 角藤 壮*; 田中 孝幸*; 嶋野 寛之*; 諸橋 裕子; 畠山 知圭*; 中島 準作; 石山 正弘
Nuclear Instruments and Methods in Physics Research A, 1063, p.169300_1 - 169300_7, 2024/06
被引用回数：3 パーセンタイル：86.15(Instruments & Instrumentation)A system for locating radioactive substances using a hexapod robot equipped with a Compton camera and light detection and ranging camera was developed, and its performance evaluation test was conducted at FUGEN, a nuclear facility owned by Japan Atomic Energy Agency. In the test, by projecting images of radioactive substances acquired with the Compton camera onto a three-dimensional model of the work environment acquired with a light detection and ranging camera, the locations where radioactive substances have accumulated and the dose rate is higher than the surrounding area were successfully visualized and identified.
前田 匡樹*; 田邉 匡生*; 西脇 智哉*; 青木 孝行*; 堂埼 浩二*; 西村 康志郎*; 藤井 翔*; 上野 文義; 田中 章夫*; 鈴木 裕介*; et al.
Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 10 Pages, 2024/03
This study develops assessment methods necessary to obtain a long-term structural integrity outlook for reactor buildings that suffered from the 2011 Great East Japan Earthquake disaster in which access to the site was extremely limited due to high radiation dose rates and high contamination. It is one of the "Nuclear science and technology and human resource development promotion projects" implemented by the Japan Atomic Energy Agency (JAEA) International Collaborative Research Center for Decommissioning and Environment (CLADS) in FY2021 to 2023. This paper introduces an outline and overview of the project.
石田 武和*; Vu, TheDang*; 宍戸 寛明*; 相澤 一也; 奥 隆之; 及川 健一; 原田 正英; 小嶋 健児*; 宮嶋 茂之*; 小山 富男*; et al.
Journal of Low Temperature Physics, 214(3-4), p.152 - 157, 2024/02
被引用回数：0 パーセンタイル：0.00(Physics, Applied)We built a new cryostat to apply a current-biased kinetic inductance detector (CB-KID) for conducting neutron transmission imaging of room temperature samples under pulsed neutrons. A Wood's metal alloy of melting temperature 75.2
C was placed at room temperature to inspect the measurement system at J-PARC. Since one of the four phases of Wood's metal is a fine Cd-rich needle phase (width 
25 m and length 5 mm), it is suitable for observing fine mosaic structure selectively by neutron imaging. The spatial resolution of the CB-KID imager was estimated as 10 m by using a Gd Siemens-star pattern. The CB-KID system is useful to conduct transmission imaging for various materials rather easily at room temperature.
Ge藤原 秀紀*; 中谷 泰博*; 荒谷 秀和*; 金井 惟奈*; 山神 光平*; 濱本 諭*; 木須 孝幸*; 関山 明*; 田中 新*; 海老原 孝雄*; et al.
New Physics; Sae Mulli, 73(12), p.1062 - 1066, 2023/12
We have performed soft X-ray absorption spectroscopy (XAS) on the heavy fermion superconductor CeNiGe to examine the local 4
electronic structure. The XAS spectra are qualitatively explained by ionic calculations, indicating a degree of localized character of the 4 states, while sizable 
-hybridization effects are also observed in the XAS spectra and those magnetic circular dichroism. In addition, the temperature dependence of linear dichroism in the XAS spectra indicates that the ground state symmetry is 
, and the excited states with 
symmetry is above 390 K.
佐藤 修彰*; 桐島 陽*; 佐々木 隆之*; 高野 公秀; 熊谷 友多; 佐藤 宗一; 田中 康介
燃料デブリ化学の現在地, 178 Pages, 2023/11
東京電力福島第一原子力発電所(1F)事故の廃炉作業は、燃料デブリの試験的取り出しや、その後の計画の検討が進められているが、今後も長期間を要する見込みであり、次世代への廃炉やデブリに関わる科学技術の継承、すなわち人材育成が重要かつ不可欠といえる。そのために、廃炉に特化した内容についての具体的な教科書が必要と考えた。1Fの燃料デブリに関しては、まだまだ、十分なことが分かっておらず、詳細についての記述は難しい。しかしながら、事故後12年を経過し、1Fの状況について分かってきたこともあり、また、過去の過酷事故の例を合わせて現状を整理してみることは、これからの展開に必要不可欠である。そこで、廃炉や燃料デブリに関する研究開発に携わってきた専門家、研究者により、固体化学や溶液化学、分析化学、さらには放射化学、放射線化学の観点から、燃料デブリ化学研究のこれまでの進展を本書「燃料デブリ化学の現在地」としてまとめた。
symmetry for anisotropic hybridization in the heavy-fermion superconductor CeNiGe藤原 秀紀*; 中谷 泰博*; 荒谷 秀和*; 金井 惟奈*; 山神 光平*; 濱本 諭*; 木須 孝幸*; 山崎 篤志*; 東谷 篤志*; 今田 真*; et al.
Physical Review B, 108(16), p.165121_1 - 165121_10, 2023/10
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)We report the ground-state symmetry of the Ce 4 states in the heavy-fermion superconductor CeNiGe, yielding anisotropic hybridization between the Ce 4 states and conducting electrons. By analyzing linear dichroism in soft X-ray absorption and core-level hard X-ray photoemission spectra, the 4 symmetry is determined as 
-type , promoting predominant hybridization with the conducting electrons originating from the Ge site. The band structures probed by soft X-ray angle-resolved photoemission indicates that the Ge 4
components contribute to the band renormalization through the anisotropic hybridization effects, suggesting that the control of the electronic structures of Ge orbital gives an impact to achieve the exotic phenomena in CeNiGe.
single crystals based on Bragg-dip analysis using a delay-line superconducting sensor宍戸 寛明*; Vu, TheDang*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; 宮嶋 茂之*; et al.
Journal of Applied Crystallography, 56(4), p.1108 - 1113, 2023/08
被引用回数：2 パーセンタイル：41.77(Chemistry, Multidisciplinary)Recent progress in high-power pulsed neutron sources has stimulated the development of the Bragg dip and Bragg edge analysis methods using a two-dimensional neutron detector with high temporal resolution to resolve the neutron energy by the time-of-flight method. A delay-line current-biased kinetic inductance detector (CB-KID) is a two-dimensional superconducting sensor with a high temporal resolution and multi-hit capability. Here, it is demonstrated that a delay-line CB-KID with a 
B neutron conversion layer can be applied to high-spatial-resolution neutron transmission imaging and spectroscopy up to 100 eV. Dip structures are observed in the transmission spectra of YbSn single crystals, induced by Bragg diffraction and nuclear resonance absorption. The orientation mapping of YbSn crystals is successfully drawn based on the analysis of observed Bragg dip positions in the transmission spectra.
大島 宏之; 森下 正樹*; 相澤 康介; 安藤 勝訓; 芦田 貴志; 近澤 佳隆; 堂田 哲広; 江沼 康弘; 江連 俊樹; 深野 義隆; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
ナトリウム冷却高速炉(SFR: Sodium-cooled Fast Reactor)の歴史や、利点、課題を踏まえた安全性、設計、運用、メンテナンスなどについて解説する。AIを利用した設計手法など、SFRの実用化に向けた設計や研究開発についても述べる。
and SrLaCuNbO; Spin-
quasi-square-lattice 
-
Heisenberg antiferromagnets渡邊 正理*; 栗田 伸之*; 田中 秀数*; 植野 航*; 松井 一樹*; 後藤 貴行*; 萩原 雅人
Physical Review B, 105(5), p.054414_1 - 054414_12, 2022/02
被引用回数：7 パーセンタイル：53.46(Materials Science, Multidisciplinary)We report the magnetic properties of the double perovskites SrLaCuSbO (SLCSO) and SrLaCuNbO (SLCNO). The temperature dependence of the magnetic susceptibilities of both com-pounds shows a broad maximum characteristic of an 
= 1/2 square lattice Heisenberg antiferromagnet. Magnetic ordering occurs at 
= 13.6 and 15.7 K for SLCSO and SLCNO, respectively. Neutron powder diffraction measurements reveal contrasting spin structures in both compounds. The spin structures of SLCSO and SLCNO below are N
el antiferromagnetic and collinear antiferromagnetic, respectively. This result demonstrates that the nearest-neighbor interaction is dominant in SLCSO, whereas the next-nearest-neighbor interaction is dominant in SLCNO. The magnitude of the ordered moment was evaluated at 3.5 K to be 
= 0.39(3) 
for SLCSO and 0.29(2) for SLCNO, which are significantly smaller than those calculated using linear spin wave theory. We infer that the small ordered moment is caused by the effect of exchange bond randomness arising from the site disorder of Sr and La ions.
宍戸 寛明*; 西村 和真*; Vu, TheDang*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; et al.
IEEE Transactions on Applied Superconductivity, 31(9), p.2400505_1 - 2400505_5, 2021/12
被引用回数：1 パーセンタイル：6.73(Engineering, Electrical & Electronic)中性子イメージングは、重金属に対する高透過性、軽元素に対する高感度、同位体と中性子との特異な核反応による同位体選択性などの中性子ビームの特徴を活かした非破壊検査の有力な手段の一つである。本研究では、超伝導検出器である電流バイアス運動インダクタンス検出器(CB-KID)を用いて、パルス中性子源を用いた飛行時間法による波長分解中性子イメージングを行った。遅延時間型CB-KIDを用いて、GdAl単結晶を成長させたGd-Al合金試料の中性子透過像を取得した。その結果、単結晶はAl-Gd合金全体に渡って、形状,分布ともに良好に観察することができた。また、中性子の波長0.03nm以上でGdによる特徴的な中性子の吸収を確認した。さらに、15m
12mという限られた検出面で、同位体と中性子の核反応によって生じる
Gd共鳴ディップを観測することができた。また、Gdの共鳴ディップを用いてGd選択的イメージングを行ったところ、中性子の波長幅が1pmという限られた範囲で、明確なGd核の元素選択イメージング像を取得することに成功した。
Vu, TheDang; 宍戸 寛明*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; 宮嶋 茂之*; et al.
Nuclear Instruments and Methods in Physics Research A, 1006, p.165411_1 - 165411_8, 2021/08
被引用回数：2 パーセンタイル：24.88(Instruments & Instrumentation)We found that the sizes of the Gd islands determined from the transmission image correlated strongly with those determined from the SEM image. We demonstrated the CB-KID could be used to identify (1) tiny voids in a thermally sprayed continuous Gd
O
film in and (2) various mosaic morphologies and different eutectic microstructures in Wood's metal samples. The fact that the CB-KID system could be used to identify features of samples with a wide distribution of sizes and thicknesses is promising for real application of the device for imaging samples of interest to material scientists. Operating the CB-KID at higher temperatures appreciably improved the efficiency for simultaneously identifying the X and Y positions of hotspots. We also compared the detection efficiency with the PHITS simulations. We now plan to improve the detection efficiency by increasing the thickness of the B neutron conversion layer
西村 昇一郎*; 鳥居 寛之*; 深尾 祥紀*; 伊藤 孝; 岩崎 雅彦*; 神田 聡太郎*; 川越 清以*; Kawall, D.*; 河村 成肇*; 黒澤 宣之*; et al.
Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08
被引用回数：19 パーセンタイル：83.44(Optics)As a method to determine the resonance frequency, Rabi-oscillation spectroscopy has been developed. In contrast to conventional spectroscopy which draws the resonance curve, Rabi-oscillation spectroscopy fits the time evolution of the Rabi oscillation. By selecting the optimized frequency, it is shown that the precision is twice as good as conventional spectroscopy with a frequency sweep. Furthermore, the data under different conditions can be treated in a unified manner, allowing more efficient measurements for systems consisting of a limited number of short-lived particles produced by accelerators such as muons. We have developed a fitting function that takes into account the spatial distribution of muonium and the spatial distribution of the microwave intensity to apply this method to ground-state muonium hyperfine structure measurements at zero field. It was applied to the actual measurement data, and the resonance frequencies were determined under various conditions. The result of our analysis gives 
= 4 463 301.61 
0.71 kHz.
宍戸 寛明*; Vu, TheDang*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; 宮嶋 茂之*; et al.
Journal of Physics; Conference Series, 1975, p.012023_1 - 012023_8, 2021/07
被引用回数：0 パーセンタイル：0.00(Engineering, Electrical & Electronic)The current-biased kinetic-inductance detector (CB-KID) is a solid-state superconducting neutron detector with high spatial and temporal resolutions, and multi-hit tolerance. We demonstrate high temperature operation of CB-KID at 7.9 K with the delayline method. High temperature operation reduces imaging pixel size by suppressing signal propagation velocity. High spatial neutron transmission image for a mixed metal alloy consisting of heavy elements Sm and Sn is successfully constructed. We also examine the capability of element discrimination imaging based on the resonance dip analysis.
Vu, TheDang; 宍戸 寛明*; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 宮嶋 茂之*; 奥 隆之; 曽山 和彦; 相澤 一也; et al.
Superconductor Science and Technology, 34(1), p.015010_1 - 015010_10, 2021/01
被引用回数：6 パーセンタイル：35.89(Physics, Applied)We demonstrated that a four-readout superconducting neutron imaging system shows good spatial heterogeneity and linearity using the delay-line method. We examined the precise pattern of a B-dot-array absorber and found the X-direction pitch (Px) = 250.7 um with a scatter of (Hx)= 5.4 um and the Y-direction pitch (Py)= 249.1 um with a scatter of (Hy)= 3.4 um while the B dot array was fully extended toward the X direction across the detector sensitive area. We consider that this demonstrates detection with good spatial homogeneity and conclude. The transmission-imaging system is suitable for use at pulsed neutron facilities. We also reported a clear transmission image of tiny screws and nuts, and ladybug (insect). We recognize that further efforts to improve the detection efficiency are necessary to make using the detector more practical.
Rodriguez, G.*; Varaine, F.*; Costes, L.*; Venard, C.*; Serre, F.*; Chanteclair, F.*; Chenaud, M.-S.*; Dechelette, F.*; Hourcade, E.*; Plancq, D.*; et al.
EPJ Nuclear Sciences & Technologies (Internet), 7, p.15_1 - 15_8, 2021/00
フランス(CEAおよびFRAMATOME)と日本(原子力機構、三菱重工業および三菱FBRシステムズ)は、ナトリウム冷却高速炉の概念に関する共通の技術的知見を確立するための研究開発協力を実施した。これは、フランス/日本の両方で利用し得る実現可能な共通の設計コンセプトを開発する方法について日仏共同で検討を進めたものである。本論文は、これらナトリウム冷却高速炉の設計コンセプトに関する共同設計検討の概要をまとめたものである。
矢野 緑里; 伊藤 貴之*; 田中 裕介*; 松岡 大祐*; 荒木 文明*; Czauderna, T.*; Stephens, K.*
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.201 - 208, 2020/10
気候モデルの調整には複雑な過程が必要なため、可視化を用いた分析は気候モデルやそのモデルの変数、出力結果を評価・理解する上で重要な役割を果たす。仮想現実(VR)技術は3次元可視化に効果的であり、近年、よりさまざまな科学データの可視化分析に用いられている。しかし、ユーザーの操作方法や観察対象の形状の特徴によってはVR空間の利点をうまく活用できない状況がある。そこで、そうした状況を解決するために画像ベースの視点選択手法を提案し、モード水領域の形状をもとにシミュレーションと観測の海洋状態の差異を把握することを目指す。この視点選択では、シミュレーションデータと観測データから抽出したモード水領域の形状を比較するときの評価基準を考慮している。本論文では、この視点選択手法を2種類の形状比較事例に適用し、比較形状の類似度合いについて考察した。
田中 伸幸; 八巻 徹也*; 浅野 雅春*; 寺井 隆幸*
Journal of Membrane Science, 587, p.117171_1 - 117171_9, 2019/10
被引用回数：10 パーセンタイル：33.86(Engineering, Chemical)熱化学水素製造法ISプロセスでは、HI-I-HO (HIx)溶液のHI濃縮のため、イオン交換膜を用いた電解電気透析法(EED)が適用されている。本報では、濃縮に伴う溶液濃度の変化が膜のH
透過性能に対して与える影響について、導電率(
)及び輸率(
)の2つの指標を用いて、Nafion212及び放射線グラフト膜に対して実験的及び理論的に評価した。EEDの数理モデルに基づく理論解析から、及びはH及びI
イオンの膜に対する含有量及び膜中の拡散係数により決まることが示される。また、実験結果から、イオン含有量に対するHIx溶液濃度依存性は十分小さいことが示され、イオンの拡散係数に対する溶液濃度依存性が及びの濃度依存性に対する支配因子となることが明らかとなった。加えて、本報では膜中のH及びIの拡散機構について考察し、各イオンの拡散に対して、I及びHOが強く関与していることが示唆された。これは、膜に対するI及びHOの親和性を制御することで、H透過性能を制御可能であることを示すものである。
