A new neutron scattering method on hydrogen researches has been developed with the pulsed neutron source. Here, Q-dependencies of inelastic neutron scattering intensities from hydrogen are measured in all directions of hydrogen compounds, and more detailed information of the hydrogen wave function and hydrogen potential is obtained. The new information strongly supports that the “self-trapped state” with hydrogen atom is realized in many materials.

Full-fledged neutronic study on neutron sources at an accelerator driven neutron source was started at Hokkaido University in Japan. The methane cold moderator was firstly developed and then a quasi-elastic spectrometer was constructed. They were transferred to KEK neutron source, KENS. After then, by using the Hokkaido University neutron source (HUNS), we developed for J-PARC a coupled hydrogen moderator that is the most efficient cold moderator. The pulsed neutron imaging is one of unique experiments. Owing to a compact neutron source with the cooperative use of the large facilities the pulsed neutron imaging has been developed and expanding its application fields, which lead to the imaging instrument RADEN.

Active focusing schemes of pulsed neutron beams in transverse or longitudinal direction are demonstrated, which are useful for efficient utilizations of precious neutrons. They use the time of flight information for the active controls of the focusing. The modulating permanent magnets can focus the pulse white neutron beams in transverse directions, when the modulation is synchronized with the neutron pulses. Because diffracting lenses have less sensitivities on the alignment tolerances than reflecting devices, the handling of the lenses are fairly easy. Since the magnetic lens has no material on the beam path, no absorption nor scattering disturbs the neutron orbits. Magnifying imaging of electrodes in a Li battery is one of useful applications of the lens. The longitudinal focusing can be achieved by an active control of the RF frequency of a spin flipper with a gradient magnetic field, which accelerates/decelerates neutrons and manipulates the longitudinal distribution of the neutrons. It should be useful for rebunching the longitudinally diffusing neutrons for neutron EDM search or making the wavelength uniform for monochromatic beam applications. Both the active controls of the transverse and longitudinal manipulations of the neutron phase space distribution are useful techniques for better utilization of precious neutrons.

PLANET is the first neutron powder diffractometer dedicated to high-pressure and high-temperature experiments in the world. The six-axis press designed for this beamline enables routine data collection at pressures and temperatures up to 10 GPa and 2000 ℃. In this article, we introduce how the PLANET had been constructed.

Recently, we have developed the experimental setup for high pressure neutron diffraction experiment with using Hybrid-Anvil-Cell in combination with high flux cold neutron time of flight (TOF) diffractometer WISH at ISIS. By using this unique setup, we have succeeded in measuring pressure induced magnetic Bragg reflections for the multiferroic compounds CuFeO₂ and TbMnO₃. The former shows pressure induced polar magnetic phases up to 7.9 GPa. For the latter compound, we have determined the magnetic structures under not only high pressure (5 GPa) but also high magnetic field (8 T) condition. In this article, I would like to show utilization of the combination, and encourage researchers in other fields as well as multiferroics to use the unique combination.

In the past decade, ionic liquids (ILs) have gained increasing attention in many fields, since they possess several unique properties, such as negligible vapor pressure, high ionic conductivity, and wide range of solubility. One of the most interesting features in imidazolium-based ILs is a higher order structure reflecting the nanoscale segregation of polar and nonpolar domains. The structure and dynamics of the ILs were investigated by means of neutron diffraction and quasielastic scattering techniques. It was found that the nanostructure drastically grows upon cooling. Furthermore, we have successfully observed the relaxation of nanostructure, ionic diffusion, imidazolium relaxation, and alkyl reorientation separately. From the anion/cation dependence of the relaxation processes, it is concluded that the hierarchical dynamics in the ILs is predominantly governed by the Coulombic interaction between the polar parts of cations and anions.

Magnetic skyrmions are of increasing interest in condensed matter physics, because of their topologically-nontrivial vortex-like spin textures. We investigated effects of uniaxial stress on the skyrmion state in a chiral metallic compound MnSi, revealing that phase transition between a (topologically trivial) conical magnetic phase and the skyrmion phase can be controlled by applying uniaxial stress of up to 100 MPa. We directly observed the pressure induced phase transition from the skyrmion phase to the conical phase by using the TOF-SANS instrument TAIKAN in MLF of J-PARC.

The neutron spin echo (NSE) technique is an essential spectroscopic method, which has achieved the highest neutron energy resolution at the present moment. NSE with a pulsed neutron source makes it possible to scan a wide spatiotemporal space very efficiently. Kyoto University and KEK are jointly installing two types of NSE spectrometers at BL06, that is, a neutron resonance spin echo (NRSE) instrument and a modulated intensity by zero effort (MIEZE) instrument. Both NRSE and MIEZE make use of neutron resonance spin flippers, which made it possible to design and install compact and multiple spectrometers machines in a narrow space. We named the spectrometers “VIN ROSE” (VIllage of Neutron ResOnance Spin Echo spectrometers), which will spawn a new field of spectroscopic methods. In this manuscript, the characteristics, the current status, and the future plan of “VIN ROSE” are reviewed.

The Energy-Resolved Neutron Imaging System “RADEN” has been constructed at the beam line of BL22 in the Materials and Life Science Experimental Facility (MLF) of J-PARC. This instrument is the first beam line dedicated for the pulsed neutron imaging experiment in the world. In November 2014, the first neutron beam was delivered to this beam line successfully, and on-beam commissioning study has started. The user programs started partially in 2015. In this paper, we introduce the specifications of our new beam line and present some results of on-beam commissioning and some demonstration study.