The J-PARC project has been conducted jointly by JAERI and KEK since 2001. This paper reports an overview and current status of the project. The high intensity proton accelerator consists of a 400 MeV Linac, a 3 GeV synchrotron and 50 GeV synchrotron to deliver MW level pulsed proton beam to experimental facilities. The MW proton power will provide an advanced scientific experimental research complex aiming at making breakthroughs in materials and life science with neutron and muon, nuclear and elementary physics, etc. Regarding the project being close to its completion in 2008, this paper describes the overview of J-PARC project with emphasis of the Materials and Life Science Experimental Facility, in which the MW pulsed neutron and muon sources, are placed to provide high quality neutron and muon beams to the world wide users.

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Over view of the neutron target system and instrument suite of J-PARC is described. The neutron facility of J-PARC, JSNS, will be operated from May 2008. JSNS will be a 1 MW pulsed spallation neutron source. About 10 instruments of high performance are under construction to be ready by the Day-One.

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At the next generation neutron source in J-PARC, a new biological diffractometer, IBARAKI Biological Crystal Diffractometer (iBIX), is under construction, which is designed so that it can measure crystals with the cell edges measuring up to c.a. 150 Å and the improved measurement efficiency will be more than 100 times larger than that of the present excellent diffractometer BIX-4 at JRR-3 in JAEA. In this paper the current status of the construction of iBIX is overviewed with expected high performances and new developments in chemistry and life science are predicted from recent results of neutron crystallography at JRR-3.

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Here we describe two neutron powder diffractometers, iMATERIA and SHRPD, at the Materials and Life Science Experimental Facility in J-PARC. iMATERIA (IBARAKI Materials Design Diffractometer) has been constructed to be a high throughput versatile diffractometer enabling materials scientists to use it like a chemical analytical instrument in their material development processes. Typical measuring time to obtain ‘Rietveld-quality’ data is several minutes for the sample size of laboratory X-ray diffractometer. On the other hand, SHRPD (Super High Resolution Powder Diffractometer) has been constructed by J-PARC to promote the best science using the best resolution in the world (Δd/d=0.03%) . Two instruments will be ready by the Day-One.

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The technique of small-angle neutron scattering has been used to study structures of size between about 1 nm and 10μm in materials and life sciences. This article introduces the smaller-angle neutron scattering instrument projected in J-PARC, which will produce new development in nanostructure analysis.

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Design concept of High-intensity total diffractometer of J-PARC is wide-Q range measurements with the highest neutron intensity by the pulsed neutron source. The resolution of the diffractometer is reasonable for crystalline materials and the diffractometer will cover very wide research fields in terms of nano structure and/or non-crystalline materials. Hydrogen absorption mechanism will be intensively investigated with the diffractometer.

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The high-pressure and high-temperature material science beamline has been approved for the construction in J-PARC. We are going to install two types of high-pressure devices in the beamline. One is a large volume multi anvil device for the generation of high temperature and high pressure up to 2000 K and 15 GPa. The other one is an opposed sintered diamond anvils for generating pressures higher than 30 GPa. The outline of the beamline and recent progress are introduced in this review article.

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The Engineering Materials Diffractometer TAKUMI designed to solve many problems in materials science and engineering including investigations of stresses and crystallographic structures within engineering components is now being developed at J-PARC. TAKUMI views a decoupled-poisoned liquid H₂ moderator with the primary and secondary flight paths of 40 m and 2.0 m, respectively. A curved supermirror neutron guide with the total length of 30 m is installed in between the primary flight path. TAKUMI has a pair main detector with the scattering angle of 90°. The best resolution of this instrument is 0.15%, which corresponds to the strain value of about 75×10^-6. The incident fluxes simulated using a Monte Carlo simulation for a wavelength bandwidth of 0.8-4.31 Å are 4.8×10⁷n/cm²/s at high intensity mode, and 2.2×10⁷n/cm²/s at high resolution mode. The construction is now in a middle stage where some parts are in installation. The construction is planned to be completed as the first phase on April 2008, and the commissioning program will be started during 2008.

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The instrumental design of an indirect geometry crystal analyzer spectrometer: DNA which is scheduled to be constructed in the Material and Life Science experimental Facility (MLF) at J-PARC, is reported in this article. This spectrometer is mainly aimed at searching for the biomolecular dynamics related to its functionality. Therefore, it is requested to measure the high quality inelastic scattering spectra with only several mg order biomolecular sample in the plenty of wide range of energy and momentum transfers.

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The construction of the following three chopper spectrometers are in progress at Japan Proton Accelerator Research Complex (J-PARC) : the High Resolution Chopper Spectrometer for high resolution experiments in wide energy range, the Cold Neutron Chopper Spectrometer for high resolution experiments at low energies and the 4d Space Access Neutron Spectrometer for investigations of high-Tc superconductors. Also, the proposal for the construction of the Versatile Inelastic Neutron Spectrometer for high flux experiments in wide energy range has been approved. The performance of these chopper spectrometers are described here.

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Neutron reflectometry is a very powerful and essential technique for structural studies on material interface with high depth resolution. Currently, a neutron reflectometer with horizontal sample geometry is being constructed on one of the neutron beam lines at a high-intensity pulsed-neutron source of Material and Life Science Facility, the Japan Proton Accelerator Research Complex (J-PARC), though it is not fully funded yet. The large gain in neutron flux at the J-PARC makes time-resolved reflectivity measurements of the order of minutes or even shorter, and also weak off-specular scattering measurements possible. The reflectometer will be equipped with state-of-the-art neutron optics, a position-sensitive detector with high counting rate and high spatial resolution, and a polarized neutron handling system. It will also have a grazingincidence small-angle scattering option to observe non-layered structures, and a neutron spin-echo option to directly probe interfacial dynamics in the order of neV. Much progress is expected in understanding the interfacial phenomena or interfacial functions by using the J-PARC neutron reflectometer.

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The user program of J-PARC/MLF is overviewed. Since MLF will be one of the major neutron facilities in the world, an international standard system for the user program is expected. It is also expected to establish a system to promote users from industries. The MLF user program is based on the IUPAP recommendation on the selection of proposals. Both open and closed accesses, biannual, regular, rapid accesses, etc. will be provided. All the features in the system are being introduced to maximize both scientific and engineering outputs from MLF.

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Advanced neutron instrumentations are key to accelerated progress of high intense pulsed neutron research at J-PARC, SNS and ISIS-TS2. Current status of development of scintillating and gaseous neutron detectors, application of neutron reflective and magnetic optics, and soft ware development for large amount data acquisition at J-PARC, are described.

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Hydrogen atoms and water molecules around proteins and nucleic acids play a crucial role in many physiological functions. Neutron diffraction provides an experimental method of directly locating hydrogen atoms. (a) Since almost all the H atom positions can be identified experimentally, the geometrical details of certain types of H-bonds can be visualized and (b) as far as mechanistic implications are concerned, the identification of protonation and deprotonation states of certain important amino acid residues can be carried out. (c) The hydration structure around proteins and the hydration networks around DNA oligomers have been successfully characterized in several outstanding cases.
These will open the new field beyond the folding structure of bio-macromolecules such as:
1) Recognition of proteins and nucleic acids through the network structure of water molecules surrounding bio-macromolecules, and
2) The nature of chemical bond in proteins and nucleic acids elucidated by the accumulation of accurate structural information of hydrogen atoms.

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Inelastic neutron scattering technique is a useful and powerful tool to investigate the intramolecular dynamics in biological macromolecules. Some spectrometers for inelastic scattering measurements applicable to macromolecules will be equipped in the J-PARC facility. Here, we overview the neutron inelastic scattering experiments in the past and discuss feature prospects on inelastic experiments targeting biological macromolecules.

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The application to single crystal neutron structural analysis is overviewed. Special attention is paid to the pulse neutron method, which will be available soon under J-PARC project in Japan. New proposal and preliminary experiment using Sirius at KENS are described.

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The capability of powder diffraction has greatly increased in X-ray diffraction field since the advent of synchrotron light source, particularly third generation synchrotron source, such as SPring-8. In neutron field, J-PARC is about to start. This means we will have advanced powder diffraction instruments in both X-ray and neutron diffraction fields. The capability of powder diffraction is surely affected by the method used in data analysis. The most common analytical method is Rietveld refinement. Recently, the sophisticated analytical method called MEM/Rietveld, become powerful tool to extract the structural information included in the accurately measured experimental data. In this article, possibilities of powder diffraction utilizing advanced neutron source, i.e. J-PARC and/or advanced neutron and X-ray sources simultaneously, will be described bearing in mind that improvement of the advanced analytical method would occur.

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The exchange of some hydrogen atoms with the other hydrogen atoms in the crystallinestate reactions, in which the reaction proceeds with retention of the single crystal form, can be directly observed by single crystal neutron diffraction technique if only the transferred hydrogen atoms were replaced with deuterium atoms before the photoirradiation. The method was successfully applied in the photoisomerization of three kinds of cobalt complex crystals and the mechanism in each reaction has been made clear.

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Materials and Life Science Facility (MLF) in Japan Proton Accelerator Complex (J-PARC), which is one of the most powerful pulse neutron scattering facilities in the world, will provide first neutron beam in May, 2008. In the article we review the expected soft materials researches, especially polymer researches in J-PARC/MLF based on the current neutron researches in three fields; mesoscopic structure studies using small-angle scattering, surface and interfacial studies by reflectivity and slow dynamics by inelastic and gasielastic scattering, especially by the neutron spin-echo technique.

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It is great pleasure that the first pulsed neutron beam will be delivered to Materials and Life Science Facility in J-PARC on May, 2008. In the last quarter of a century, synchrotron radiation has opened new scientific windows of mineralogy, especially a field of mineral physics at high pressure. In the next several 10 years, we believe that the newly dedicated pulsed neutron source facility in J-PARC will provide us many opportunities to explore the next new world of mineralogy. In this paper we will give a brief overview of mineral sciences by neutron scattering and introduce our research project about the water-mineral interaction in the Earth by using the pulsed neutron source.

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