Status of the neutron time-of-flight single-crystal diffraction data-processing software STARGazer

矢野 直峰*; 山田 太郎*; 細谷 孝明*; 大原 高志; 田中 伊知朗*; 新村 信雄*; 日下 勝弘*

Acta Crystallographica Section D; Structural Biology (Internet), 74(11), p.1041 - 1052, 2018/11

https://doi.org/10.1107/S2059798318012081

STARGazer is a data processing software for neutron time-of-flight (TOF) single-crystal diffraction data collected by the IBARAKI Biological Crystal Diffractometer (iBIX) at the Japan Proton Accelerator Research Complex (J-PARC). This software creates hkl intensity data from three-dimensional (x, y, TOF) diffraction data. STARGazer is composed of both a data processing component and a data visualization component. This article describes the status of data processing software STARGazer and its data processing algorithms.

Structure analysis and derivation of deformed electron density distribution of polydiacetylene giant single crystal by the combination of X-ray and neutron diffraction data

田代 孝二*; 日下 勝弘*; 細谷 孝明*; 大原 高志; 塙坂 真*; 吉澤 功徳*; 山元 博子*; 新村 信雄*; 田中 伊知朗*; 栗原 和男*; et al.

Macromolecules, 51(11), p.3911 - 3922, 2018/06

https://doi.org/10.1021/acs.macromol.8b00650

The crystal structure of polydiacetylene giant single crystal has been analyzed on the basis of the two different methods of wide-angle neutron diffraction and X-ray diffraction. The X-ray result gives us the total electron density distribution. The neutron result tells the positions of atomic nuclei. As a result, the so-called bonded (or deformed) electron density, i.e., the electron density distribution due to the conjugation among the covalently bonded atoms along the polymer chain, can be estimated using the two information. The present report is the first example of the application of X-N method to the synthetic polymer species.

PASCAL信頼性向上ワーキンググループ活動報告; 平成27年度

Li, Y.; 林 翔太郎*; 板橋 遊*; 永井 政貴*; 関東 康祐*; 鈴木 雅秀*; 眞崎 浩一*

JAEA-Review 2017-005, 80 Pages, 2017/03

JAEA-Review-2017-005.pdf:16.85MB

日本原子力研究開発機構では、原子炉圧力容器(RPV)の構造健全性評価手法の高度化を目的に、中性子照射脆化を考慮して、加圧熱衝撃等の過渡事象が発生した場合のRPVの破損確率や破損頻度を評価する確率論的破壊力学解析コードPASCALを開発し、最新知見に基づきその機能の高度化を進めてきた。RPVの構造健全性評価において確率論的手法の活用が期待される中で、RPVの健全性評価に係る取組みを促進するためには、PASCALの確率変数、評価機能、評価モデル等を含めた機能検証を行い、その検証過程を整理するとともに、検証結果を取りまとめておくことが必要不可欠である。こうした背景を踏まえ、開発機関以外の当該分野に関する専門家の下で、PASCALの確率論的破壊力学ソルバーであるPASCAL3をソースコードレベルで機能検証することにより、本コードの信頼性を向上させることを目的として、PASCAL信頼性向上WGを設立した。一年の活動を通じて、PASCAL3が十分な信頼性を有することが確認された。本報は、PASCAL信頼性向上WGの平成27年度における活動内容及び活動結果についてまとめたものである。

Rapid measurement scheme for texture in cubic metallic materials using time-of-flight neutron diffraction at iMATERIA

小貫 祐介*; 星川 晃範*; 佐藤 成男*; 徐 平光; 石垣 徹*; 齋藤 洋一*; 轟 秀和*; 林 眞琴*

Journal of Applied Crystallography, 49(5), p.1579 - 1584, 2016/10

AA2016-0186.pdf:1.13MB

https://doi.org/10.1107/S160057671601164X

The authors have developed texture measurement system on a time-of flight neutron diffractometer, iMATERIA (BL20, MLF/J-PARC, Japan). Quantitative Rietveld texture analysis for a duplex stainless steel was possible with one neutron beam exposure for several minutes without sample rotation. The minimum number of diffraction spectra required for the Rietveld texture analysis was experimentally determined as 100. The suggested rapid measurement scheme used 132 spectra and determined volume fractions of texture components in both ferrite and austenite phases, quantitatively. This quantitative and rapid measurement scheme was established by utilizing the features of iMATERIA as a powder diffractometer, i.e. fairly high resolution in d-spacing and numerous detectors equipped in a wide range of scattering angle.

Inter-atomic force constants of BaF by diffuse neutron scattering measurement

佐久間 隆*; Makhsun*; 酒井 竜太郎*; Xianglian*; 高橋 東之*; Basar, K.*; 井川 直樹; Danilkin, S. A.*

AIP Conference Proceedings 1656, p.020002_1 - 020002_4, 2015/04

https://doi.org/10.1063/1.4917089

10Kおよび295KにてBaFの中性子散漫散乱測定を実施し、295Kにおいて、振動する散漫散乱強度パターンが観察された。この散漫散乱パターンよりF-F間の相関効果を解析することができ、この相関効果とDebye-Waller因子から、295KにおけるBaFの最近接および第2近接原子間の力定数は各々4.40, 2.30eV/と求められた。

飛行時間法中性子回折によるバルク材料集合組織測定技術の開発

徐 平光; 星川 晃範*; 林 真琴*; 秋田 貢一; 森井 幸生*; 石垣 徹*

日本材料学会第48回X線材料強度に関するシンポジウム講演論文集, p.7 - 9, 2014/07

Time-of-flight neutron diffraction may evidently accelerate the bulk texture measurement speed through the proper combination of multiple orientations distributed neutron detectors and the simultaneous multiple diffraction peak acquisition, and only few sample rotations are needed to be carried out. In addition to the omega-axis rotatable sample changer, a dedicated omega/chi two-axis rotatable goniometer is under urgent development. It is highly expected to play an important role to evaluate the bulk texture evolution of advanced materials during thermomechanical controlling process. Though the intrinsic difference in neutron diffraction spectra from different orientations (determined by each set of Bragg angle/azimuthal angle) evidently increases the technical difficulty in rapid texture analysis, the development of Materials Analysis Using Diffraction (MAUD, developed by Luca Lutterotti, et al.) and other relevant software/programs are bringing us much convenience. Moreover, in order to increase the accessibility to neutron diffraction bulk texture measurement instruments, the various cooperative researches and the mail-in services are being planned.

Development of a high power diplexer with short-slotted metal half mirrors for electron cyclotron current drive

三枝 幹雄*; 渥美 幸平*; 山口 智輝*; 小田 靖久; 坂本 慶司

Fusion Engineering and Design, 88(6-8), p.964 - 969, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.163

A neoclassical tearing mode (NTM) which is a resistive MHD instability driven by plasma pressure gradient in tokamak plasma is one of the key issues giving the upper limitation of plasma performance. It can be controlled by the local current drive in a magnetic island with electron cyclotron current drive (ECCD). Up to now, ECCD with pulse modulated gyrotron operation at duty of 50% have been done to drive current into only O-point. For improving a stabilizing efficiency of NTM, the fast directional switch had been developed. It makes the duty of ECCD system to 100% by switching beam direction for tracking the rotating O-point of a magnetic island of NTM. The new type diplexer as a fast switching device of high power millimeter wave was proposed and had been simulated with finite difference time domain (FDTD) method. A proposed diplexer consists of a ring corrugated circular waveguide, a pair of mitre-bends, and a pair of half mirrors. The low power switching operation of the mock-up diplexer with long-slotted metal half mirrors at the two frequency bands (137 GHz and 170 GHz) was veried. In this paper, the low power test results of the diplexer with new short-slotted metal half mirrors at a frequency band of 170 GHz is reported.

高速炉におけるガス巻込み現象の防止基準,1; 数値解析によるガス巻込み現象再現精度の検証

大島 宏之; 田中 伸厚*; 江口 譲*; 西村 元彦*; 功刀 資彰*; 内堀 昭寛; 伊藤 啓; 堺 公明

日本原子力学会和文論文誌, 11(4), p.316 - 328, 2012/12

https://doi.org/10.3327/taesj.J11.047

ナトリウム冷却高速炉の安定運転において、自由表面渦によるガス巻込みの防止が重要であるため、著者らはCFDに基づくガス巻込み評価手法の開発を行っている。本研究では、ガス巻込み解析を行うためのCFD手法に関する検討を行った結果、ガス巻込み現象の適切な数値解析を行うためには、十分な格子解像度、高精度離散化手法、過度に渦を減衰させない乱流モデルなどが必要であることを明らかにした。

中性子回折によるフェライト単相鋼のひずみ時効硬化異方性の検討

鈴木 徹也*; 山中 啓輔*; 石野 まゆ子*; 篠原 康浩*; 長井 健介*; 津留 英司*; 徐 平光

鉄と鋼, 98(6), p.262 - 266, 2012/06

https://doi.org/10.2355/tetsutohagane.98.262

The work-hardening characteristics of anisotropic tensile deformations and the corresponding residual strain changes of pre-strained ferritic steels without and with ageing treatment were investigated by using angle dispersive neutron diffraction and electron back-scattering diffraction. The plastic deformation along the pre-strained direction leads to evident work-hardening at the beginning stage, showing discontinuous yielding behavior. Comparably, the plastic deformation perpendicular to the pre-strained direction shows continuously yielding. The tensile and compressive residual strains were found in the 200 and 110 grains along the pre-strained direction, respectively. It is also found that the difference in various oriented grains after strain ageing become more evident along the pre-strained direction but smaller perpendicular to the pre-strained direction, revealing a higher work hardening capability in the former case than in the latter case.

Hydrogen-bond network and pH sensitivity in transthyretin; Neutron crystal structure of human transthyretin

横山 武司*; 水口 峰之*; 鍋島 裕子*; 日下 勝弘*; 山田 太郎*; 細谷 孝明*; 大原 高志*; 栗原 和男; 友寄 克亮*; 田中 伊知朗*; et al.

Journal of Structural Biology, 177(2), p.283 - 290, 2012/02

https://doi.org/10.1016/j.jsb.2011.12.022

Transthyretin (TTR) is a tetrameric protein associated with human amyloidosis. In vitro, the formation of amyloid fibrils by TTR is known to be promoted by low pH. Here we show the neutron structure of TTR, focusing on the hydrogen bonds, protonation states and pH sensitivities. A large crystal was prepared at pD 7.4 for neutron protein crystallography. Neutron diffraction studies were conducted using the IBARAKI Biological Crystal Diffractometer with the time-of-flight method. The neutron structure solved at 2.0 resolution revealed the protonation states of His88 and the detailed hydrogen-bond network depending on the protonation states of His88. This hydrogen-bond network is composed of Thr75, Trp79, His88, Ser112, Pro113, Thr118-B and four water molecules, and is involved in both monomer-monomer and dimer-dimer interactions, suggesting that the double protonation of His88 by acidification breaks the hydrogen-bond network and causes the destabilization of the TTR tetramer. In addition, the comparison with X-ray structure at pH 4.0 indicated that the protonation occurred to Asp74, His88 and Glu89 at pH 4.0. Our neutron model provides insights into the molecular stability of TTR related to the hydrogen-bond network, the pH sensitivity and the CH...O weak hydrogen bond.