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佐野 亜沙美; 服部 高典; 町田 真一*; 阿部 淳*; 舟越 賢一*
no journal, ,
PLANETは超高圧下における中性子回折実験を実現するためにMLF, J-PARC内に設置された、高圧実験専用のビームラインである。精密なスリットやラジアルコリメーターなどの光学系を有し、試料が小さく、中性子実験との相性が悪い高圧実験においても質の高いデータの取得が可能となっている。ビームラインでは実験の目的に応じて6軸型マルチアンビルププレスや、パリ-エジンバラプレス、MITOシステムなど様々な高圧試料環境が利用可能であり、技術開発により実験の適用圧力温度範囲も広がっている。発表ではこれら最近の技術開発の紹介と、成果のハイライトを紹介する。
中島 健次
no journal, ,
JRR-3は多目的研究炉である。1990年に完了した大規模な改修後、原子炉は20MWの熱出力で稼働している。原子炉ホールには水平ビーム管7本、ガイドホールには熱導管2本と冷導管3本が設置されており、日本原子力研究開発機構、東京大学、東北大学、茨城大学、京都大学、量子科学技術研究開発機構(QST)などが運用する中性子測定装置28台が設置されている。JRR-3は2011年の東日本大震災後、新規制基準に対応した補強工事のため停止したが、2021年にユーザープログラムが再開された。10年間のユーザー運用中断にもかかわらず、現在JRR-3では中性子科学が活発に行われている。JRR-3は基礎科学から産業応用まで幅広い分野で成果をあげている。この講演では、JRR-3で行われている中性子科学の概要、現状、将来の展望について述べる。
大原 高志; 鬼柳 亮嗣; 中尾 朗子*; 宗像 孝司*; 石川 喜久*; 森山 健太郎*
no journal, ,
Hydrogen bonds in molecular crystals are one of the research areas extensively investigated by the single-crystal neutron diffraction technique. SENJU, a time-of-flight Laue-type single-crystal neutron diffractometer at J-PARC, is one of the world's limited single-crystal neutron diffractometer capable of measuring a sub-millimeter size molecular crystal. In this presentation, the authors will show what kind of structural research of hydrogen bonds in functional molecular crystals, e.g., proton transfers in temperature-induced spin-transfer metal complexes and a salt-cocrystal continuum formation in a photo-functional organic crystal, conducted at SENJU.
大原 高志
no journal, ,
J-PARCの単結晶中性子回折計SENJUの現状と最近のトピックスについて紹介する。
Qin, T. Y.*; Hu, F. F.*; 徐 平光; Zhang, H.*; Zhou, L.*; Ao, N.*; Su, Y. H.; 菖蒲 敬久; Wu, S. C.*
no journal, ,
Gradient compressive residual stress with a depth of several millimeters exists in railway S38C hollow axles subject to surface induction hardening, which is a challenging problem for structural integrity assessment. To address this, the axial, hoop, and radial residual stress values inside the axles are measured by neutron diffraction technology. By integrating the limited neutron diffraction data, an innovative nodal stress based coordinate assignment (INSCA) approach was then proposed, to numerically reconstruct the global initial residual stress field in three dimensions for S38C axles. The comparison between simulations and experiments clearly show that approximately 515 MPa (axial), 710 MPa (hoop), and 43 MPa (radial) compressive residual stresses were retained underneath the induction hardened martensite layer, which also validates the newly-developed INSCA method. By including the measured axial- and hoop-direction residual stresses, the crack propagation behavior of railway S38C axles were investigated, in terms of fracture mechanics. It was clearly shown that the presence of compressive residual stress leads to a lower driving force of crack propagation, in terms of stress intensity factor range (
). Such smaller also indicates that this compressive residual stress can effectively prolong the service lifetime of high-speed railway axles subjected to induction hardening treatment.
篠原 武尚; 甲斐 哲也; 及川 健一; Su, Y. H.; 土川 雄介; 林田 洋寿*; Parker, J. D.*; 松本 吉弘*
no journal, ,
In J-PARC, we have constructed the energy-resolved neutron imaging system, named "RADEN", as the dedicated beamline for energy-dependent neutron imaging experiments. This instrument was designed to fully conduct Bragg edge imaging, neutron resonance absorption imaging and pulsed polarized neutron imaging together with the state-of-the-art conventional neutron imaging. RADEN is now used by users in various scientific and industrial fields. Especially industrial applications on the hydrogen fuel cells and Li ion batteries for the electric vehicles are intensively conducted to improve their performance due to the recent movement toward carbon neutrality. In this presentation, development of pulsed neutron imaging techniques at J-PARC will be introduced and results of application studies will be discussed.
Song, F.; 樋口 雄紀*; 日比 章五*; 吉宗 航*; 加藤 悟*; 篠原 武尚
no journal, ,
In this work, we have applied the energy-selective neutron radiography to visualize the freezing and thawing of water in different cavity layers of a fuel cell by taking cross-sectional neutron transmission images, as a preliminary experiment for further operando water/ice identification observations on PEFCs. A miniature size of a fuel cell, which consisted of gas diffusion layers (GDLs) and aluminum frames with gas channels produced by 3D printing technique, was prepared as a model cell sample. This model fuel cell was filled with water and cooled by a Peltier cooler down to -10 degree C. Consecutive high-resolution energy-selective neutron imaging was conducted throughout the freezing process at the RADEN instrument in J-PARC MLF. By taking the ratio of logarithms of neutron transmission between long and short wavelength neutrons, we defined a water/ice identification parameter to confirm freezing of water within the cell. This parameter was spatially resolved on the neutron transmission images to map the water/ice distribution in each layer of the model fuel cell as it was cooled to sub-zero temperatures. In the presentation, we will discuss the spatial and temporal resolution capacities of the high-resolution energy-selective neutron imaging at the RADEN instrument, and show results of the water/ice identification experiments on the cross-sectional observation of the PEFC.
Harjo, S.; Gong, W.; 川崎 卓郎; Mao, W.; 山崎 倫昭*
no journal, ,
Many advanced metallic materials composed of not only multiphases but also multi-morphological structures within one of the constituent phases, so-called multimodal structure metallic material. In this presentation, we will introduce and discuss our methods to understand the deformation behavior in metallic materials with multimodal structure, using a case of strengthening of 
Mg and long-period stacking ordered phases in a Mg-Zn-Y alloy by hot-extrusion with low extrusion ratio.
Gong, W.; 川崎 卓郎; Mao, W.; 伊東 達矢; Harjo, S.
no journal, ,
Neutrons are used to investigate stresses and crystallographic microstructures inside engineering materials, taking advantage of their large penetrating power and the ability to see the arrangement of atoms by diffraction methods. A pulsed neutron diffractometer has been developed in J-PARC and operated for more a decade. The present status of the diffractometer and some highlights will be introduced.
川北 至信; 菊地 龍弥*
no journal, ,
Ge、Si、Sn、Pb、Zn、Cd、Hg、Ga、Bi等の単元素液体金属は剛体球モデルとはかけ離れた複雑な構造を示す。それらの構造因子S(Q)は、非対称であったり肩構造を持つ第一ピークを有している。また単純なカチオン、アニオンの二元素系から成る溶融塩の中で、固相で超イオン伝導体であるAgIやCuIはカチオンとアニオンの運動が非対称である特異なイオンダイナミクスを液体相で示す。そのような液体の複雑性を理解するために、コヒーレント(構造可干渉性)な中性子準弾性散乱(QENS)は、測定スペクトルにすべての対相関の時間発展の情報を含んでいるので、非常に有効な手段である。この発表では、超イオン伝導メルトCuIと複雑液体金属Biに関して、モード分布解析およびVan Hove関数解析を通じたアプローチによる結果を紹介する。
松浦 直人*; 川北 至信; 山田 武*; 富永 大輝*; 玉造 博夢; 中川 洋; 大内 啓一*
no journal, ,
DNA is a time-of-flight backscattering spectrometer installed at the Materials and Life Science Experimental Facility (MLF) in Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Its purpose is revealing pico to nano second dynamics in a wide field of sciences and industrial applications including soft matter, bio-molecules, chemical molecules, battery, catalyst, and magnetism. A pulse-shaping chopper equipped at the 7.75 m position from the coupled moderator makes this instrument relatively short in the neutron guide length (42 m from the moderator to the sample position). Its maximum rotation speed of 300 Hz provides us fine energy resolutions up to 1.4 micro second for a sample with dimension of 1 cm wide and 1cm tall. Changing phases of the slit opening of the chopper enables us to select energy bands and even to scan a wide energy transfer range with the highest resolution. Two types of analyzer mirrors of Si111 and Si311 cover large momentum transfer ranges of 0.08 to 1.98 
and 1.79 to 3.39 , respectively. Frequently used measurement modes are a high-flux mode without rotating the chopper and a high-resolution mode with 225 Hz. Those provides 12 and 3.6 micro eV energy resolutions for a large sample of 1.4 cm wide and 4 cm tall. The back-coat by neutron absorber such as Gd and Gd
O
for Si analyzer mirrors serves us in realizing extremely high signal-to-noise ratio of 
, which allows us to obtain QENS spectra from a tiny amount of sample or a dilute protein solution. Various conditions of sample environment are available; cryo-furnaces (4 K to 700 K), a 2K cryostat, a top-loading sample stick for applying electric field, a humidity control system, a cryostat with a samples changer for three samples, an inner atmosphere controller for cryo-furnaces and so on. A high temperature furnace up to 1000K, 3.5 Tesla cryo-magnet and a sample changer for 20 samples are under commissioning.