Neutron scattering and diffraction have a unique position for characterizing the atomic-scale disorder in liquid and amorphous metals. In this article, the history of liquid structure research is briefly summarized and the development of pulsed neutrons based on accelerators is referred to be a pioneering achievement by Japan. Analysis of liquid structure is not a straight work even by advanced experimental observations and computer simulations at the moment, but I believe that the difficulties facing us will be certainly overcome by young peoples in the next generation.

My first encounter with neutron scattering research on low-dimensional magnetism at the Hahn-Meitner Institut under the supervision of Prof. H. Dachs and Prof. M. Steiner, where it all began, is accounted for. The polarized neutron analysis research on low-dimensional magnetism at the Institut Laue Langevin under the supervision of Dr. R. Pynn is also reported. I would like to dedicate this article to late Prof. H. Dachs expressing my deepest gratitude for his warm guidance during the early period of my neutron science carrier.

The effect of an antagonistic salt on the phase behavior and nanoscale structure of a mixture of water / organic solvent was investigated by visual inspection, optical microscope, and small-angle neutron scattering (SANS). The addition of the antagonistic salt, namely sodium tetraphenylborate (NaBPh₄), induces the shrinking of the two-phase region in contrast to the case in which a normal (hydrophilic) salt is added. Below the phase separation point, the SANS profiles cannot be described by the Ornstein-Zernike function owing to the existence of a long-range periodic structure. With increasing salt concentration, the critical exponents change from the values of 3D-Ising and approach those of 2D-Ising. Furthermore, an ordered phase with multilamellar (onion) structures was confirmed in an off-critical mixture of D₂O and 3-methylpyridine containing 85 mM of a NaBPh₄ although no surfactants or polymers are contained.

  Electrical conductivity, synchrotron X-ray diffraction, and time-of-flight neutron diffraction measurements were carried out for ⁷Li₇P₃S₁₁ metastable crystal and (⁷Li₂S)₇₀(P₂S₅)₃₀ glass. Reverse Monte Carlo modeling based on the neutron and X-ray data showed three-dimensional structures of ⁷Li₇P₃S₁₁ metastable crystal and (⁷Li₂S)₇₀(P₂S₅)₃₀ glass. A detailed polyhedral analysis of the three-dimensional atomic configuration yielded the spatial distribution of LiS₄ tetrahedra ([LiS₄] units) and S₄ tetrahedra (without Li⁺ ion; [S₄] units) in ⁷Li₇P₃S₁₁ metastable crystal and (⁷Li₂S)₇₀(P₂S₅)₃₀ glass. When an ac-[S₄] unit is recognized as a fully acceptable unit of the Li⁺ ion, the coordination number of ac-[S₄] units around a [LiS₄] unit for ⁷Li₇P₃S₁₁ metastable crystal was estimated to be twice as large as that for (⁷Li₂S)₇₀(P₂S₅)₃₀ glass on average. Such structural characteristics in ⁷Li₇P₃S₁₁ metastable crystal and (⁷Li₂S)₇₀(P₂S₅)₃₀ glass are intimately related to electrochemical properties.

IBARAKI Materials Design Diffractometer (iMATERIA) is a high-throughput powder diffractometer, and has a vacuum chamber in order to reduce a background from the air scattering. Each sample is typically measured in several minutes by used 1MW pulsed proton beams, and must be placed in the vacuum chamber before being measured. The process of re-establishing the vacuum would become a bottleneck when samples are exchanged. To reduce exchange time, we developed and manufactured an automatic sample changer that can handle a large number of samples through the vacuum chamber.

The paper describes what the DAQ-Middleware is, first. Secondly, the application to Neutron Experiment will be shown. Finally, the commissioning will be summarized.

In this year, I have received the “Special Award” from the Japanese Society for Neutron Science. The citation of the award is “Searching for new superconductors and also the general contribution to the neutron scattering science”. On this occasion, I would like to describe my neutron scattering carriers, in particular focused on the observation of orbital ordering and magnetic chirality studies.

We have developed a prototype time-resolved neutron imaging detector employing a micro-pattern gaseous detector known as the micro-pixel chamber (μPIC) coupled with a field-programmable-gate-array-based data acquisition system. Our detector system combines 100μm-level spatial and sub-μs time resolutions with a low gamma sensitivity of less than 10^-12 and high data rates, making it well suited for applications in neutron radiography at high-intensity, pulsed neutron sources. In the present paper, we introduce the detector system and present several test measurements performed at NOBORU (BL10), J-PARC to demonstrate the capabilities of our prototype. We also discuss future improvements to the spatial resolution and rate performance.

Triple-axis spectrometer is a multi-purpose instrument for powder neutron diffraction, single crystal neutron diffraction, powder inelastic neutron scattering, single crystal inelastic neutron scattering, and neutron polarization analysis. In this lecture how to use the triple-axis spectrometer is explained for the beginners.

We review polarized neutron scattering techniques using triple-axis spectrometers.

Introduction of neutron structure analysis using single crystal is described. Starting two-dimensional case, principle of diffraction geometry is discussed, and then it is extend to three-dimensional measurements. For that experiment, two dimensional detector and four-circle diffractometer are used, and the methodology of these diffractometer is described. Then, the basic theory of crystal and magnetic structure analysis is given. Finally, some example of crystal and magnetic structure analysis are shown.