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論文

Experimental visualization of water/ice phase distribution at cold start for practical-sized polymer electrolyte fuel cells

樋口 雄紀*; 吉宗 航*; 加藤 悟*; 日比 章五*; 瀬戸山 大吾*; 伊勢川 和久*; 松本 吉弘*; 林田 洋寿*; 野崎 洋*; 原田 雅史*; et al.

Communications Engineering (Internet), 3, p.33_1 - 33_7, 2024/02

The automotive industry aims to ensure the cold-start capability of polymer electrolyte fuel cells (PEFCs) for developing fuel cell electric vehicles that can be driven in cold climates. Water and ice behavior is a key factor in maintaining this capability. Previously reported methods for visualizing water and/or ice are limited to small-sized PEFCs ( $$<$$ 50 cm$$^{2}$$), while fuel cell electric vehicles are equipped with larger PEFCs. Here, we developed a system using a pulsed spallation neutron beam to visualize water distribution and identify water/ice phases in practical-sized PEFCs at a cold start. The results show direct evidence of a stepwise freezing behavior inside the PEFC. The produced water initially accumulated at the center of the PEFC and then froze, followed by PEFC shutdown as freezing progressed. This study can serve as a reference to guide the development of cold-start protocols, cell design, and materials for next-generation fuel cell electric vehicles.

論文

In situ neutron imaging of lithium-ion batteries during heating to thermal runaway

野崎 洋*; 近藤 広規*; 篠原 武尚; 瀬戸山 大吾*; 松本 吉弘*; 佐々木 厳*; 伊勢川 和久*; 林田 洋寿*

Scientific Reports (Internet), 13, p.22082_1 - 22082_8, 2023/12

 被引用回数:0 パーセンタイル:0.00(Multidisciplinary Sciences)

Lithium ion batteries (LIBs) have become essential components that power most current technologies, thus making various safety evaluations necessary to ensure their safe use. Heating tests remain the most prominent source of safety issues. However, information on the phenomena occurring inside batteries during heating has remained inaccessible. In this study, we demonstrate the first in situ neutron imaging method to observe the internal structural deformation of LIBs during heating. We developed an airtight Al chamber specially designed to prevent radioactive contamination during in situ neutron imaging. We successfully observed the liquid electrolyte fluctuation inside a battery sample and the deformation of the protective plastic film upon heating up to thermal runaway.

論文

Corrigendum to "Visualization of the working fluid in a flat-plate pulsating heat pipe by neutron radiography" [International Journal of Heat and Mass Transfer 185 (2022) 122336]

安田 陽介*; 松本 吉弘*; 篠原 武尚; 鍋島 史花*; 堀内 敬介*; 永井 大樹*

International Journal of Heat and Mass Transfer, 213, p.124291_1 - 124291_2, 2023/10

 被引用回数:0 パーセンタイル:0.96(Thermodynamics)

Behaviors of the working fluid in a flat-plate pulsating heat pipe (PHP), made of aluminum alloy, in the bottom- and top-heating orientations were visualized by neutron radiography. The results indicate that the initial distribution of the working fluid does not affect the startup characteristics of oscillation of the working fluid in regard to the specifications of flat-plate PHP used in this study.

論文

3D water management in polymer electrolyte fuel cells toward fuel cell electric vehicles

吉宗 航*; 樋口 雄紀*; 加藤 晃彦*; 日比 章五*; 山口 聡*; 松本 吉弘*; 林田 洋寿*; 野崎 洋*; 篠原 武尚; 加藤 悟*

ACS Energy Letters (Internet), 8(8), p.3485 - 3487, 2023/08

 被引用回数:3 パーセンタイル:74.57(Chemistry, Physical)

A multiscale water visualization technique for polymer electrolyte fuel cells was established by using ${it operando}$ multiprobe radiography with pulsed spallation neutron and synchrotron X-ray sources. The three-dimensional water distribution revealed that water back-diffusion from the cathode to the anode significantly contributes to the drainability of practical polymer electrolyte fuel cells toward fuel cell electric vehicles.

論文

Fast phase differentiation between liquid-water and ice by pulsed neutron imaging with gated image intensifier

伊勢川 和久; 瀬戸山 大吾*; 樋口 雄紀*; 松本 吉弘*; 長井 康貴*; 篠原 武尚

Nuclear Instruments and Methods in Physics Research A, 1040, p.167260_1 - 167260_10, 2022/10

 被引用回数:1 パーセンタイル:28.09(Instruments & Instrumentation)

This paper reports on development of pulsed neutron imaging for phase differentiation between liquid water and ice with introduction of a gated image intensifier. Previous neutron-imaging systems for phase differentiation between liquid-water and ice, on the other hand, had some issues with temporal resolution, horizontal distribution of neutron wavelength, and field-of-view size. By using energy-selected pulsed neutron imaging with an optical image intensifier, the authors have achieved liquid-water/ice phase identification with a shorter temporal resolution than before with a suitable field of view area to observe commercial PEFCs.

論文

Catalog of gamma-ray glows during four winter seasons in Japan

和田 有希*; 松本 崇弘*; 榎戸 輝揚*; 中澤 知洋*; 湯浅 孝行*; 古田 禄大*; 米徳 大輔*; 澤野 達哉*; 岡田 豪*; 南戸 秀仁*; et al.

Physical Review Research (Internet), 3(4), p.043117_1 - 043117_31, 2021/12

In 2015 the Gamma-Ray Observation of Winter Thunderstorms (GROWTH) collaboration launched a mapping observation campaign for high-energy atmospheric phenomena related to thunderstorms and lightning discharges. This campaign has developed a detection network of gamma rays with up to 10 radiation monitors installed in Kanazawa and Komatsu cities, Ishikawa Prefecture, Japan, where low-charge-center winter thunderstorms frequently occur. During four winter seasons from October 2016 to April 2020, in total 70 gamma-ray glows, minute-lasting bursts of gamma rays originating from thunderclouds, were detected. Their average duration is 58.9 sec. Among the detected events, 77% were observed in nighttime. The gamma-ray glows can be classified into temporally-symmetric, temporally-asymmetric, and lightning-terminated types based on their count-rate histories. An averaged energy spectrum of the gamma-ray glows is well fitted with a power-law function with an exponential cutoff, whose photon index, cutoff energy, and flux are 0.613 $$pm$$ 0.009, 4.68 $$pm$$ 0.04 MeV, and (1.013 $$pm$$ 0.003) $$times$$ 10$$^{-5}$$ erg cm$$^{-2}$$s$$^{-1}$$ (0.2-20.0 MeV), respectively. The present paper provides the first catalog of gamma-ray glows and their statistical analysis detected during winter thunderstorms in the Kanazawa and Komatsu areas.

論文

Visualization of the boron distribution in core material melting and relocation specimen by neutron energy resolving method

阿部 雄太; 土川 雄介; 甲斐 哲也; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03

Since the hardness of fuel debris containing boride from B$$_{4}$$C pellet in control rod is estimated to be two times higher as that of oxide, such as UO$$_{2}$$ and ZrO$$_{2}$$, distribution of such boride in the fuel debris formed in the Fukushima-Daiichi Nuclear Power Plants may affect the process of debris cutting and removal. The high neutron absorption of boron may affect the possibility of re-criticality during the process of debris removal. Therefore, boride distribution in fuel debris is regarded as an important issue to be addressed. However, boron tends to have difficult in quantification with conventionally applied methods like EPMA and XPS. In this study, accelerator-driven neutron-imaging system was applied. Since boron is the material for neutron absorption, its sensitivity in terms of neutron penetration through specimens is concerned. To adjust neutron attenuation of a specimen to suit a particular measurement by selecting the neutron energy range, we focused on the energy resolved neutron imaging system RADEN, which utilizes wide energy range from meV to keV. Development of a method to visualize boron distribution using energy-resolved neutrons has been started. In this presentation the authors show the status of the development of a method utilizing energy-resolved neutrons and provide some outcome from its application to the Core Material Melting and Relocation (CMMR)-0 and -2 specimens.

論文

Feasibility study of PGAA for boride identification in simulated melted core materials

土川 雄介; 阿部 雄太; 大石 佑治*; 甲斐 哲也; 藤 暢輔; 瀬川 麻里子; 前田 亮; 木村 敦; 中村 詔司; 原田 正英; et al.

JPS Conference Proceedings (Internet), 33, p.011074_1 - 011074_6, 2021/03

福島原子力発電所の解体作業では、溶融した燃料棒に含まれるホウ素分布を事前に把握することが重要である。溶融燃料棒の模擬試験体を用意し、ホウ素やホウ化物の含有量を調査する研究が行われてきた。本研究では、その一環として中性子を用いたホウ素並びにホウ化物分布の測定技術開発を行った。ホウ素の中性子吸収に伴う即発ガンマ線を測定し、ホウ素量や二次元分布を測定した。また、n(B,$$alpha$$$$gamma$$)反応における478keV$$gamma$$線は、ホウ素の化合状態により、$$gamma$$線ピークの幅が変化することが知られている。このことを用い、特に溶融燃料棒周辺に存在することが予測されているZrBやFeBといったホウ化物の識別可能性について調査した。測定はJ-PARC/MLFのANNRI, NOBORU, RADENにて行った。これらの解析結果について報告する。

論文

Pulsed neutron imaging for differentiation of ice and liquid water towards fuel cell vehicle applications

樋口 雄紀*; 瀬戸山 大吾*; 伊勢川 和久; 土川 雄介; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 長井 康貴*

Physical Chemistry Chemical Physics, 23(2), p.1062 - 1071, 2021/01

 被引用回数:6 パーセンタイル:49.65(Chemistry, Physical)

本研究は、パルス中性子源施設において行われた水と氷のイメージングに関する最初の報告である。固体高分子燃料電池(PEFC)内部の水分分布を可視化するために中性子イメージングを利用した。特に、エネルギー分解中性子イメージングは、液体の水と氷を区別することができる手法であり、氷点下の環境で動作するPEFCにおける氷の形成を調べるのに効果的である。水氷識別は、低中性子エネルギーにおいて液体の水と氷の断面積が異なることを利用した。実際のPEFC内の混相流(気体・液体・固体)の過渡的な凍結・融解現象を高い空間分解能で定量的に観測するためには、高強度で広いエネルギー範囲を持つパルス中性子ビームが最適である。本研究では、PEFCの流路を模擬して細い毛細管に封入した水を用い、パルス中性子ビームを照射して氷、液体水、過冷却水を識別し、毛細管内の水の凍結・融解現象を明らかにした。さらに、実物大の燃料電池を用いたその場観察へのステップとして、-30$$^{circ}$$Cまで冷却可能なサブゼロ環境チャンバーを製作し、大視野(300mm$$times$$300mm)での液体の水・氷分布の観察を可能にした。

論文

Thundercloud project; Exploring high-energy phenomena in thundercloud and lightning

湯浅 孝行*; 和田 有希*; 榎戸 輝揚*; 古田 禄大; 土屋 晴文; 久富 章平*; 辻 結菜*; 奥田 和史*; 松元 崇弘*; 中澤 知洋*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2020(10), p.103H01_1 - 103H01_27, 2020/10

 被引用回数:14 パーセンタイル:72.90(Physics, Multidisciplinary)

We designed, developed, and deployed a distributed sensor network aiming at observing high-energy ionizing radiation, primarily gamma rays, from winter thunderclouds and lightning in coastal areas of Japan. Starting in 2015, we have installed, in total, more than 15 units of ground-based detector system in Ishikawa Prefecture and Niigata Prefecture, and accumulated 551 days of observation time in four winter seasons from late 2015 to early 2019. In this period, our system recorded 51 gamma-ray radiation events from thundercloud and lightning. Highlights of science results obtained from this unprecedented amount of data include the discovery of photonuclear reaction in lightning which produces neutrons and positrons along with gamma rays, and deeper insights into the life cycle of a particle-acceleration and gamma-ray-emitting region in a thunder-cloud. The present paper reviews objective, methodology, and results of our experiment, with a stress on its instrumentation.

論文

Development of three-dimensional distribution visualization technology for boron using energy resolved neutron-imaging system (RADEN)

阿部 雄太; 土川 雄介; 甲斐 哲也; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08

Boron carbide is used as a neutron-absorbing material in Fukushima-Daiichi Nuclear Power Station (1F), producing borides that are twice as hard as oxides (such as UO$$_{2}$$ and ZrO$$_{2}$$). The high neutron absorption of boron affects the evaluation of re-criticality during the process of debris retrieval. Therefore, it is important not only to determine the presence of boron but also to investigate the distribution of boron inside the material in a non-destructive manner during decommissioning. To address the uncertainties in the core material relocation behavior of boiling water reactor (BWR) during a severe accident (SA), solidified melt specimens of a simulated fuel assembly were prepared by plasma heating. If core material melting and relocation (CMMR) specimens can be used to estimate the B distribution in 1F Unit-3, that will provide valuable information in the decommissioning of 1F. To address this, the authors focused on the energy-resolved neutron imaging system, RADEN, which utilizes a wide energy range, from meV to keV. This is an innovative three-dimensional analysis technology for boride distribution that affects the evaluation of hardness and re-criticality. In the calibration standard samples (Zr$$_{x}$$B$$_{1-x}$$ and Fe$$_{x}$$B$$_{1-x}$$), there was a good correlation between boron concentration and the energy-dependence of the cross sections of cold and epi-thermal neutrons. In the CMMR specimens, boron distribution was confirmed from the contrast difference between cold and epi-thermal neutrons. In the future, the results of calibration standard samples will be applied to the results of CMMR specimens. With this method, three-dimensional boron distribution will be measured, and the understanding of boride distribution 1F Unit-3 will be improved, which may be reflected in an improved SA code.

論文

Development of event-type neutron imaging detectors at the energy-resolved neutron imaging system RADEN at J-PARC

Parker, J. D.*; 原田 正英; 林田 洋寿*; 廣井 孝介; 甲斐 哲也; 松本 吉弘*; 中谷 健; 及川 健一; 瀬川 麻里子; 篠原 武尚; et al.

Materials Research Proceedings, Vol.15, p.102 - 107, 2020/05

At the RADEN instrument, we take advantage of the accurate measurement of neutron energy by time-of-flight to perform energy-resolved neutron imaging using event-type neutron imaging detectors. We are continually working to improve these detectors for better spatial resolution and shorter measurement times and, as a user facility, to improve the ease-of-use of their control and analysis software. In particular, we are actively developing a $$^{3}$$He-based gaseous micropattern detector known as the Micro-pixel chamber based Neutron Imaging Detector ($$mu$$ NID). We have recently redesigned the $$mu$$ NID control software to allow full integration into the automated experiment control system at RADEN, and we are carrying out optimization of the analysis algorithms for improved image quality and rate performance.

論文

The Energy-resolved neutron imaging system, RADEN

篠原 武尚; 甲斐 哲也; 及川 健一; 中谷 健; 瀬川 麻里子; 廣井 孝介; Su, Y. H.; 大井 元貴; 原田 正英; 飯倉 寛; et al.

Review of Scientific Instruments, 91(4), p.043302_1 - 043302_20, 2020/04

 被引用回数:51 パーセンタイル:96.36(Instruments & Instrumentation)

The energy-resolved neutron imaging system, RADEN, has been installed at the pulsed neutron source in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. In addition to conventional neutron radiography and tomography, RADEN, the world's first imaging beam-line at a pulsed neutron source, provides three main options for new, quantitative neutron imaging techniques: Bragg-edge imaging to visualize the spatial distribution of crystallographic information, resonance absorption imaging for elemental composition and temperature information, and polarized neutron imaging for magnetic field information. This paper describes the results of characterization studies of the neutronic performance and installed devices at RADEN and shows the results of several demonstration studies for pulsed neutron imaging.

論文

中性子イメージング装置RADEN(螺鈿)の活用

甲斐 哲也; 篠原 武尚; 松本 吉弘*

検査技術, 25(2), p.1 - 5, 2020/02

J-PARC物質・生命科学実験施設に設置されたエネルギー分析型中性子イメージング装置RADENは、エネルギー分析を行わない中性子ラジオグラフィ/トモグラフィの利用でも相応の役割を果たしている。本稿では、検査技術の一つとしての検討材料を提供するため、これまでにRADENで中性子ラジオグラフィ/トモグラフィの利用で得られた成果について紹介する。

論文

Pulsed neutron imaging based crystallographic structure study of a Japanese sword made by Sukemasa in the Muromachi period

及川 健一; 鬼柳 善明*; 佐藤 博隆*; 大前 良磨*; Pham, A.*; 渡辺 賢一*; 松本 吉弘*; 篠原 武尚; 甲斐 哲也; Harjo, S.; et al.

Materials Research Proceedings, Vol.15, p.207 - 213, 2020/02

Japanese swords are very attractive not only as a work of art but also a metallurgical point of view. Since Japanese vintage swords became valuable, it is indispensable to establish non-destructive analysis method to identify some peculiar characteristics. Bragg edge imaging gives real-space distributions of bulk information in a crystalline material as well as neutron tomography. In this work, we investigated crystallographic information of a Japanese sword made by Sukemasa in Izumi province in the first quarter of the 16th century. The experiments have been performed at RADEN at J-PARC. The Sukemasa sword was measured with a counting-type 2D detector and with a CCD camera. We are now analyzing the measured 2D-transmission spectra using RITS code to obtain spatial distribution of the crystallite size, the texture variation, the d110 shift and its broadening. Complementary data analysis using white beam tomography is also on going. Detailed analysis results will be presented.

論文

Feasibility study of two-dimensional neutron-resonance thermometry using molybdenum in 316 stainless-steel

甲斐 哲也; 廣井 孝介; Su, Y. H.; 瀬川 麻里子; 篠原 武尚; 松本 吉弘*; Parker, J. D.*; 林田 洋寿*; 及川 健一

Materials Research Proceedings, Vol.15, p.149 - 153, 2020/02

A two-dimensional thermometry technique based on neutron resonance reactions derives the temperature of specified elements in an object by analyzing the Doppler broadening of a neutron resonance measured by a time-analyzing neutron imaging-detector. This technique is expected to be one of the important applications of the energy-resolved neutron imaging system, RADEN, at J-PARC. The authors focused on molybdenum contained in 316 stainless-steel (with a weight fraction of 2-3 wt%). Energy-dependent transmitted neutrons were measured through a 3 mm thick 316 stainless-steel plate placed in a heater at temperatures between 23 and 500 degrees Celsius at RADEN using a gas-electron multiplier (GEM) detector. Thermal and cold neutrons were eliminated from the incident beam by a cadmium filter. The sample area within the neutron beam was 30 by 50 mm$$^2$$. The feasibility is discussed in the presentation.

論文

Neutron computed tomography of phase separation structures in solidified Cu-Co alloys and investigation of relationship between the structures and melt convection during solidification

庄司 衛太*; 磯谷 祥世*; 鈴木 陸人*; 久保 正樹*; 塚田 隆夫*; 甲斐 哲也; 篠原 武尚; 松本 吉弘*; 福山 博之*

Scripta Materialia, 175, p.29 - 32, 2020/01

 被引用回数:19 パーセンタイル:76.75(Nanoscience & Nanotechnology)

The effect of melt convection on the phase separation structures in undercooled Cu- Co alloys was investigated using the electromagnetic levitation technique, where the melt convection was controlled by applying a static magnetic field. The three-dimensional phase separation structures of the solidified Cu-Co alloys were first observed using neutron computed tomography. A large number of small spherical Co-rich phases were dispersed in the Cu-rich phase matrix when the static magnetic field was relatively small. In contrast, several coalesced Co-rich phases, which were elongated along the direction of the static magnetic field, appeared in the higher strength of static magnetic field.

論文

中性子イメージングによる純パラジウムおよびアルミニウム合金中の水素濃度解析

清水 一行*; 林田 洋寿*; 戸田 裕之*; 甲斐 哲也; 松本 吉弘*; 松本 佳久*

日本金属学会誌, 83(11), p.434 - 440, 2019/11

 被引用回数:1 パーセンタイル:6.01(Metallurgy & Metallurgical Engineering)

Neutron imaging experiment was performed to visualize the distribution of solute hydrogen in an Al-10.1%Zn-1.2%Mg alloy and a pure palladium after hydrogen charging. Changes in the contrast of neutron transmission images caused by hydrogen were clearly observed in a palladium. In the wavelength range of 2-3 AA and 5-13.5 AA, the mean neutron transmission around the center of a hydrogen-charged palladium were 0.692 and 0.511, respectively. The hydrogen content in a palladium was estimated to be 10.8 mol% from the measured neutron transmission. This study has demonstrated that hydrogen content can be analyzed by considering the wavelength dependence of neutron intensity. On the other hand, hydrogen could not be observed from the neutron transmission image in Al-Zn-Mg alloys. This was due to the low hydrogen content, which was mass ppm level even after hydrogen charging, and statistical precision was not sufficient to discuss the amount of hydrogen of the mass ppm order.

論文

Downward terrestrial gamma-ray flash observed in a winter thunderstorm

和田 有希*; 榎戸 輝揚*; 中澤 知洋*; 古田 禄大; 湯浅 孝行*; 中村 佳敬*; 森本 健志*; 松元 崇弘*; 牧島 一夫*; 土屋 晴文

Physical Review Letters, 123(6), p.061103_1 - 061103_6, 2019/08

AA2018-0706.pdf:0.79MB

 被引用回数:33 パーセンタイル:87.74(Physics, Multidisciplinary)

During a winter thunderstorm on 2017 November 24, a strong burst of gamma-rays with energies up to $$sim$$10 MeV was detected coincident with a lightning discharge, by scintillation detectors installed at Kashiwazaki-Kariwa Nuclear Power Plant at sea level in Japan. The burst had a sub-second duration, which is suggestive of photoneutron productions. The leading part of the burst was resolved into four intense gamma-ray bunches, each coincident with a low-frequency radio pulse. These bunches were separated by 0.7$$-$$1.5 ms, with a duration of $$<$$1 ms each. Thus, the present burst may be considered as a "downward" terrestrial gamma-ray flash (TGF), which is analogous to up-going TGFs observed from space. Although the scintillation detectors were heavily saturated by these bunches, the total dose associated with them was successfully measured by ionization chambers, employed by nine monitoring posts surrounding the power plant. From this information and Monte Carlo simulations, the present downward TGF is suggested to have taken place at an altitude of 2500$$pm$$500 m, involving $$8^{+8}_{-4} times10^{18}$$ avalanche electrons with energies above 1 MeV which is comparable to those in up-going TGFs.

論文

Gamma-ray glow preceding downward terrestrial gamma-ray flash

和田 有希*; 榎戸 輝揚*; 中村 佳敬*; 古田 禄大; 湯浅 孝行*; 中澤 知洋*; 森本 健志*; 佐藤 光輝*; 松元 崇弘*; 米徳 大輔*; et al.

Communications Physics (Internet), 2(1), p.67_1 - 67_9, 2019/06

 被引用回数:49 パーセンタイル:92.92(Physics, Multidisciplinary)

Two types of high-energy events have been detected from thunderstorms. One is "terrestrial gamma-ray flashes" (TGFs), sub-millisecond emissions coinciding with lightning discharges. The other is minute-lasting "gamma-ray glows". Although both phenomena are thought to originate from relativistic runaway electron avalanches in strong electric fields, the connection between them is not well understood. Here we report unequivocal simultaneous detection of a gamma-ray glow termination and a downward TGF, observed from the ground. During a winter thunderstorm in Japan on 9 January 2018, our detectors caught a gamma-ray glow, which moved for $$/sim$$ 100 s with ambient wind, and then abruptly ceased with a lightning discharge. Simultaneously, the detectors observed photonuclear reactions triggered by a downward TGF, whose radio pulse was located within $$sim$$ 1 km from where the glow ceased. It is suggested that the highly-electrified region producing the glow was related to the initiation of the downward TGF.

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