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Journal Articles

Quasielastic neutron scattering of brucite to analyse hydrogen transport on the atomic scale

Okuchi, Takuo*; Tomioka, Naotaka*; Purevjav, N.*; Shibata, Kaoru

Journal of Applied Crystallography, 51, p.1564 - 1570, 2018/12

 Times Cited Count:0 Percentile:0.01(Chemistry, Multidisciplinary)

It is demonstrated that quasielastic neutron scattering (QENS) is a novel and effective method to analyse atomic scale hydrogen transport processes occurring within a mineral crystal lattice. The method was previously characterized as sensitive for analysing the transport frequency and distance of highly diffusive hydrogen atoms or water molecules in condensed matter. Here are shown the results of its application to analyse the transport of much slower hydrogen atoms which are bonded into a crystal lattice as hydroxyls. Two types of hydrogen transport process were observed in brucite, Mg(OH)$$_{2}$$ : a jump within a single two-dimensional layer of the hydrogen lattice and a jump into the next nearest layer of it. These transport processes observed within the prototypical structure of brucite have direct implications for hydrogen transport phenomena occurring within various types of oxides and minerals having layered structures.

Journal Articles

${{it In situ}}$ neutron diffraction of iron hydride in iron-silicate-water system under high pressure and high temperature condition

Iizuka, Riko*; Yagi, Takehiko*; Goto, Hirotada*; Okuchi, Takuo*; Hattori, Takanori; Sano, Asami

Hamon, 27(3), p.104 - 108, 2017/08

Hydrogen is the most abundant element in the solar system and is considered to be one of the promising candidates of the light elements in the Earth's core. However, the amount of hydrogen dissolved in the core and its process are still unknown because hydrogen cannot be detected by X ray and easily escapes from iron at ambient conditions. In this study, we have conducted high-pressure and high-temperature in-situ neutron diffraction experiments on the iron-hydrous mineral system using PLANET in J-PARC. We observed that the water, which was dissociated from a hydrous mineral, reacted with iron to form both iron oxide and iron hydride at about 4 GPa. Iron hydride remained stable after further increase in temperature. This formation occurred at 1000K, where no materials melted. This suggests that hydrogen dissolved into iron before any other light elements dissolved in the very early stage of the Earth's evolution.

Journal Articles

Hydrogenation of iron in the early stage of Earth's evolution

Iizuka, Riko*; Yagi, Takehiko*; Goto, Hirotada*; Okuchi, Takuo*; Hattori, Takanori; Sano, Asami

Nature Communications (Internet), 8, p.14096_1 - 14096_7, 2017/01

AA2016-0524.pdf:0.73MB

 Times Cited Count:26 Percentile:88.17(Multidisciplinary Sciences)

Density of the Earth's core is lower than that of pure iron and the light element(s) in the core is a long-standing problem. Hydrogen is the most abundant element in the solar system and thus one of the important candidates. However, the dissolution process of hydrogen into iron remained unclear. Here we carry out high-pressure and high-temperature in situ neutron diffraction experiments and clarify that when the mixture of iron and hydrous minerals are heated, iron is hydrogenized soon after the hydrous mineral is dehydrated. This implies that early in the Earth's evolution, as the accumulated primordial material became hotter, the dissolution of hydrogen into iron occurred before any other materials melted. This suggests that hydrogen is likely the first light element dissolved into iron during the Earth's evolution and it may affect the behaviour of the other light elements in the later processes.

Journal Articles

Hydrogen sites in the dense hydrous magnesian silicate phase E; A Pulsed neutron powder diffraction study

Tomioka, Naotaka*; Okuchi, Takuo*; Purevjav, N.*; Abe, Jun*; Harjo, S.

Physics and Chemistry of Minerals, 43(4), p.267 - 275, 2016/04

 Times Cited Count:6 Percentile:26.06(Materials Science, Multidisciplinary)

Journal Articles

Large-volume static compression using nano-polycrystalline diamond for opposed anvils in compact cells

Okuchi, Takuo*; Sasaki, Shigeo*; Osakabe, Toyotaka; Ono, Yoshiki*; Odake, Shoko*; Kagi, Hiroyuki*

Journal of Physics; Conference Series, 215, p.012188_1 - 012188_9, 2010/03

 Times Cited Count:5 Percentile:87.1

We prepared super-hard nano-polycrystalline diamond (NPD) anvils for large-volume compression for intrinsically low-sensitivity methods of measurement, such as neutron scattering and NMR. These anvils are harder, larger and stronger than single crystal diamond anvils, so that they could play an ideal role to accept the larger forces. We tested supported and unsupported anvil geometries separately by using two types of compact high-pressure cells and could generate the pressure of 14 GPa for the sample volume of 0.1 mm$$^{3}$$ or more. The test results demonstrate a large future potential of NPD anvils for large-volume compression.

Journal Articles

Development of high-pressure technique for single-crystal magnetic neutron diffraction under 10 GPa

Osakabe, Toyotaka; Yamauchi, Hiroki; Okuchi, Takuo*

Koatsuryoku No Kagaku To Gijutsu, 20(1), p.72 - 75, 2010/02

A new hybrid-type anvil technique for high-pressure single-crystal magnetic neutron diffraction under 10 GPa is described. The hybrid anvil is composed of an opposed pair of two kinds of anvils. One is a large sapphire anvil or a supported SiC anvil and the other is a tungsten carbide (WC) anvil which has a hollow in the center of the culet. In a feasibility test of the hybrid anvil, we could generate the pressure up to 10 GPa at the load of 3.8 tons with high stability.

Journal Articles

Neutron powder diffraction under high pressure at J-PARC

Utsumi, Wataru; Kagi, Hiroyuki*; Komatsu, Kazuki*; Arima, Hiroshi*; Nagai, Takaya*; Okuchi, Takuo*; Kamiyama, Takashi*; Uwatoko, Yoshiya*; Matsubayashi, Kazuyuki*; Yagi, Takehiko*

Nuclear Instruments and Methods in Physics Research A, 600(1), p.50 - 52, 2009/02

 Times Cited Count:11 Percentile:63.13(Instruments & Instrumentation)

The application of high pressure can induce dramatic changes in the physical properties of condensed matter. Diffraction experiments under high pressure provide precise structural information, which is fundamental to understand their origin. When in situ high pressure neutron diffraction becomes possible at J-PARC, further outstanding researches are expected such as crystal structure of hydrogen-bearing materials including hydrous minerals, order-disorder transitions of minerals, structure of light element liquid at high pressure, etc.. Conceptual designs of neutron optics and high pressure devices for J-PARC are introduced.

Journal Articles

A High pressure experiment of powder neutron diffraction on the HRPD at JRR-3

Komatsu, Kazuki*; Arima, Hiroshi*; Kagi, Hiroyuki*; Okuchi, Takuo*; Sasaki, Shigeo*; Yamauchi, Hiroki; Fukazawa, Hiroshi; Igawa, Naoki; Utsumi, Wataru; Kamiyama, Takashi*

Koatsuryoku No Kagaku To Gijutsu, 18(2), p.170 - 172, 2008/05

In this short communication, we report neutron diffractions under high pressure from lead powder in a Paris-Edinburgh cell at the High Resolution Powder Diffractometer (HRPD) installed at JRR-3, Ibaraki, Japan. This is the kick-off experiment in Japan as a high pressure powder diffraction study using reactor neutron source.

Oral presentation

High-pressure powder neutron diffraction measurements using PE cell at JRR

Arima, Hiroshi; Komatsu, Kazuki*; Kagi, Hiroyuki*; Okuchi, Takuo*; Sasaki, Shigeo*; Yamauchi, Hiroki; Fukazawa, Hiroshi; Igawa, Naoki; Utsumi, Wataru; Kamiyama, Takashi*

no journal, , 

For the forward planning of high-pressure neutron diffraction study, it is meaningful to consider the use of Paris-Edinburgh (PE) high pressure cells. We conducted a first experiment for high-P powder diffraction using PE cells on the high resolution powder diffractometer (HRPD) in the reactor neutron source: JRR-3. Lead particle (Nilaco Co., 99.9999%), which has a relatively high scattering length and low absorption for neutron, was used as a sample in order to obtain the intensity data as efficient as possible. A couple of cubic BN anvils and a TiZr null metal gasket were used in order to avoid scattering from surrounding materials. The intensities of a 111 reflection, which is the strongest peak in lead sample, are 250 counts/h at ambient pressure and 80 counts/h at 30 tonnes. The pressure estimated by the obtained lattice constants at 30 tonnes was 2.9(1) GPa. These results allows us to estimate how long beam time is necessary for the potential experiments.

Oral presentation

First results on high-pressure neutron scattering experiments at Takumi in J-PARC

Hattori, Takanori; Abe, Jun; Arima, Hiroshi; Arakawa, Masashi; Komatsu, Kazuki*; Okuchi, Takuo*; Kagi, Hiroyuki; Utsumi, Wataru; Harjo, S.; Ito, Takayoshi

no journal, , 

High-pressure neutron experiments have been limited so far due to the small flux of neutron source. Now, the intense pulse neutron source offered from J-PARC opens up the opportunity. Then, we are trying to do high-pressure neutron experiments, which offers information that have been not obtained so far, such as position of light elements and atomic dynamics. In this talk, we reports first high-pressure TOF results taken at the engineering materials diffractometer TAKUMI in J-PARC, and discuss the future prospect on high-pressure neutron diffraction.

Oral presentation

A Feasibility study of neutron powder diffraction under high pressure with the Engineering Materials Diffractometer "TAKUMI" at J-PARC

Abe, Jun; Hattori, Takanori; Komatsu, Kazuki*; Arima, Hiroshi; Arakawa, Masashi*; Okuchi, Takuo*; Kagi, Hiroyuki; Yagi, Takehiko*; Uwatoko, Yoshiya*; Matsubayashi, Kazuyuki*; et al.

no journal, , 

We have examined the feasibility of in situ neutron powder diffraction under high pressure with the Engineering Materials Diffractometer "TAKUMI", which has been constructed at BL19 in the Materials and Life Science Facility (MLF) of J-PARC. We have tested two types of high pressure devices at TAKUMI, a Paris-Edinburgh press and a Palm cubic anvil cell. Neutron poder diffraction profiles of Pb placed in the high pressure devices as a standard material were collected. As results, diffraction peaks of Pb were clearly observed. In this study, it has been confirmed that in situ neutron powder diffraction under high pressure can be made with a combination of the high pressure devices and the TAKUMI at J-PARC.

Oral presentation

Strategy of high pressure research with pulsed neutron at J-PARC

Utsumi, Wataru; Kagi, Hiroyuki*; Hattori, Takanori; Arima, Hiroshi; Komatsu, Kazuki*; Abe, Jun; Nagai, Takaya*; Okuchi, Takuo*; Harjo, S.; Aizawa, Kazuya; et al.

no journal, , 

J-PARC is a new high-intensity proton accelerator research facility in Japan. It has a spallation neutron source that will produce the world highest intensity pulsed neutron. It is expected that high pressure material science and the investigation of the Earth's interior will greatly improve at J-PARC. A Paris-Edinburgh cell and a cubic anvil high pressure apparatus have been brought to an Engineering Materials Diffractometer(BL19) to conduct the first high pressure experiment. As the next stage, we are planning to construct a dedicated high pressure beamline that will open in 2011.

Oral presentation

Neutron powder diffraction under high pressure using the engineering materials diffractometer "TAKUMI"

Abe, Jun; Hattori, Takanori; Sano, Asami; Arima, Hiroshi; Fukazawa, Hiroshi; Harjo, S.; Ito, Takayoshi; Aizawa, Kazuya; Utsumi, Wataru; Komatsu, Kazuki*; et al.

no journal, , 

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 was developed at J-PARC. In addition, TAKUMI is suitable for high-pressure experiments. High-pressure devices (Paris-Edinburgh press, palm cubic anvil press and Diamond Anvil Cell) were developed for in situ neutron powder diffraction experiments under high pressures. However, to apply a these high-pressure devices to neutron diffraction, research and development is needed. Issues to be resolved selecting materials, modifying the diffraction window and reducing BKG.

Oral presentation

High pressure experiments using high-intensity pulsed neutron at "TAKUMI" in J-PARC

Abe, Jun; Arima, Hiroshi; Hattori, Takanori; Komatsu, Kazuki*; Sano, Asami; Arakawa, Masashi*; Okuchi, Takuo*; Kagi, Hiroyuki; Fukazawa, Hiroshi; Utsumi, Wataru

no journal, , 

The Engineering Materials Diffractometer "TAKUMI" has been constructed in the Materials and Life Science Experimental Facility (MLF) of J-PARC. TAKUMI is the neutron powder diffractometer which intended to estimate stress in engineering components. The optical system and the sample stage of TAKUMI are well adapted to high-pressure experiments. In order to confirm the feasibility of high-pressure neutron diffraction at TAKUMI, we have performed a number of R&Ds using a Paris-Edinburgh Press and a Palm cubic anvil cell. As results, diffraction patterns coming from small samples embedded in these high-pressure devices have been obtained. In addition, in situ neutron diffraction of ice at high-pressure and low-temperature conditions ($$sim$$ 1 GPa, $$>$$ 20 K) has been performed. Recently, the further R&Ds have been done; optimization of materials such as anvil and pressure medium, developments of focusing mirror, reduction of background and contamination noise.

Oral presentation

High-pressure neutron diffraction experiments at TAKUMI in J-PARC

Abe, Jun; Hattori, Takanori; Arima, Hiroshi; Sano, Asami; Fukazawa, Hiroshi; Utsumi, Wataru; Komatsu, Kazuki*; Arakawa, Masashi*; Iizuka, Riko*; Kagi, Hiroyuki*; et al.

no journal, , 

In order to confirm the feasibility of high-pressure neutron diffraction at TAKUMI, we have performed a number of R&Ds using a various high-pressure devices. Optimization of materials such as anvil and pressure medium and developments of collimators have made possible reduction of background and contamination noise. Incident and diffracted neutron beams travel through high-pressure device, which causes attenuation of neutron. We investigated the method of attenuation correction.

Oral presentation

High-pressure activities in the new pulsed neutron source J-PARC

Hattori, Takanori; Arima, Hiroshi; Sano, Asami; Abe, Jun; Honda, Mitsunori; Fukazawa, Hiroshi; Utsumi, Wataru; Okuchi, Takuo*; Ono, Yoshiki*; Sasaki, Shigeo*; et al.

no journal, , 

The high-pressure neutron experiments above 10 GPa are limited so far due to the small neutron flux, which is insufficient for tiny high-pressure sample. Recent construction of the intense pulsed neutron source around the world has changed the situation. Inspired by the new Japanese pulsed neutron source JSNS at J-PARC, we started the high-P neutron experiments at the already operated beamlines (TAKUMI, NOVA) and the construction of the new beamline dedicated for high-pressure use (PLANET). This talk introduces these activities.

Oral presentation

Powder neutron diffraction study using high-pressure cells at J-PARC/TAKUMI

Abe, Jun; Arima, Hiroshi; Hattori, Takanori; Sano, Asami; Fukazawa, Hiroshi; Utsumi, Wataru; Komatsu, Kazuki*; Arakawa, Masashi*; Iizuka, Riko*; Kagi, Hiroyuki; et al.

no journal, , 

We have performed high-pressure neutron diffraction experiments at TAKUMI in J-PARC. Three types of high-pressure devices are used, Paris-Edinburgh Press, Palm cubic anvil cell and NPD-DAC. Optimization of materials such as anvil and pressure medium and developments of collimators have made possible reduction of background and contamination noise. Incident and diffracted neutron beams travel through high-pressure device, which causes attenuation of neutron. We have studied the method of attenuation correction and analyzed crystal structure using corrected neutron diffraction pattern.

Oral presentation

Development of high pressure cell for neutron diffraction experiment

Sano, Asami; Komatsu, Kazuki*; Okuchi, Takuo*; Hattori, Takanori

no journal, , 

no abstracts in English

Oral presentation

Development of high pressure cell for neutron diffraction experiment

Sano, Asami; Komatsu, Kazuki*; Okuchi, Takuo*; Hattori, Takanori

no journal, , 

no abstracts in English

Oral presentation

Attenuation correction for cubic-anvil high pressure cell for neutron diffraction study under pressure

Abe, Jun; Komatsu, Kazuki*; Arima, Hiroshi*; Hattori, Takanori; Sano, Asami; Arakawa, Masashi*; Kagi, Hiroyuki; Okuchi, Takuo*; Utsumi, Wataru

no journal, , 

We have performed high-pressure neutron diffraction experiments using newly designed cubic-anvil high-pressure cell. Incident and diffracted neutron beams travel through high-pressure device, which causes attenuation of neutron. We have studied the method of attenuation correction and analyzed crystal structure using corrected neutron diffraction pattern. The total attenuation of the diffracted neutron beam is calculated by ray tracing. Neutron diffracted pattern of Al$$_{2}$$O$$_{3}$$ in cubic-anvil high-pressure device have been measured and carried out the attenuation correction. Crystal structure was analyzed by the Rietveld method. Atomic coordinates and displacement parameters of Al$$_{2}$$O$$_{3}$$ in cubic-anvil high-pressure device agreed with those obtained by using sample holder.

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