4SEASONS is a Fermi chopper spectrometer in operation at the Materials and Life Science Experimen... more 4SEASONS is a Fermi chopper spectrometer in operation at the Materials and Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC). 4SEASONS is expected to facilitate highefficiency measurements of weak inelastic signals on novel spin and lattice dynamics using thermal neutrons. The spectrometer is equipped with a coupled moderator and sophisticated components such as an elliptical converging neutron guide with high-critical-angle supermirrors, long (2.5 m) position-sensitive detectors, and a Fermi chopper appropriate for multiple-incident-energy (multi-E i) measurements by the repetition-rate multiplication technique. Herein, we discuss in detail the design and performance of the spectrometer, and present some examples of the measurements obtained using this spectrometer.
The three-dimensional atomic configuration of amorphous Ge 2 Sb 2 Te 5 and GeTe were derived by r... more The three-dimensional atomic configuration of amorphous Ge 2 Sb 2 Te 5 and GeTe were derived by reverse Monte Carlo simulation with synchrotron-radiation x-ray diffraction data. The authors found that amorphous Ge 2 Sb 2 Te 5 can be regarded as "even-numbered ring structure," because the ring statistics is dominated by four-and six-fold rings analogous to the crystal phase. On the other hand, the formation of Ge-Ge homopolar bonds in amorphous GeTe constructs both odd-and even-numbered rings. They believe that the unusual ring statistics of amorphous Ge 2 Sb 2 Te 5 is the key for the fast crystallization speed of the material.
Lead-indium phosphate glasses exhibit a number of useful properties such as a high indexof-refrac... more Lead-indium phosphate glasses exhibit a number of useful properties such as a high indexof-refraction, low preparation temperature and melt viscosity, and good chemical durability. The structure of such a glass (composition in wt. %: 65 PbO, 29 P2O5, 6 In2O3) has been investigated by total neutron scattering usin5 the GLAD diffractometer at Argonne's spallation neutron source IPNS. Peaks corresponding to the P-0, Pb-Ofin-0, and 0-0 pairs were observed in the radial distribution function. The short-range structure in the glass, in terms of average coordination numbers and bond distances, is compared with those of a pure P.705 glass and with the crystal structure of lead pyrophosphate, Pb2P207. Unlike silicate glasses in which the Si04 tetrahedra form a 3-dimensional network, the PO4 tetrahedra in phosphate glasses form a chain-like structure. The structural modification by the lead cations in phosphate glasses appears to occur mainly in the medium range-affecting the lengths and connectivity of the chain-like structure.
Previous x-ray diffraction measurements revealed the pressure-induced decomposition of an fcc-LaH... more Previous x-ray diffraction measurements revealed the pressure-induced decomposition of an fcc-LaH 2.3 into H-rich and H-poor fcc phases around 11 GPa. The present neutron diffraction measurements on LaD 2 confirm the formation of NaCl-type LaD as a counterpart of the D-rich LaD 2+δ by disproportionation. First-principle enthalpy and lattice dynamic calculations demonstrate that the NaCl-type LaH is stabilized at high pressures and can be recovered at ambient conditions. Finding the NaCl-type LaH will pave the way for investigations on the site-dependent nature of hydrogen-metal interactions.
Physics and Chemistry of Glasses-european Journal of Glass Science and Technology Part B, Dec 12, 2020
The use of high‑energy x‑ray diffraction techniques with the latest generation synchrotron source... more The use of high‑energy x‑ray diffraction techniques with the latest generation synchrotron sources has created new approaches to study quantitatively the structure of noncrystalline materials. Recently, this technique has been combined with neutron diffraction at pulsed source to provide more detailed and reliable structural information not previously available. This article reviews and summarises recent results obtained from the high energy x‑ray diffraction on several oxide glasses, SiO2, B2O3 and PbSiO3, using bending magnet beamlines at SPring‑8. In particular, it addresses the structural models of the oxide glasses obtained by the reverse Monte Carlo (RMC) modelling technique using both the high energy x‑ray and neutron diffraction data.
On April 2015, the J-PARC E56 (JSNS2: J-PARC Sterile Neutrino Search using neutrinos from J-PARC ... more On April 2015, the J-PARC E56 (JSNS2: J-PARC Sterile Neutrino Search using neutrinos from J-PARC Spallation Neutron Source) experiment officially obtained stage-1 approval from J-PARC. We have since started to perform liquid scintillator R&D for improving energy resolution and fast neutron rejection. Also, we are studying Avalanche Photo-Diodes (SiPM) inside the liquid scintillator. In addition to the R&D work, a background measurement for the proton beam bunch timing using a small liquid scintillator volume was planned, and the safety discussions for the measurement have been done. This report describes the status of the R&D work and the background measurements, in addition to the milestones required before stage-2 approval.
Understanding the structure-property relationship of glass material is still challenging due to a... more Understanding the structure-property relationship of glass material is still challenging due to a lack of periodicity in disordered materials. Here, we report the properties and atomic structure of vanadium phosphate glasses characterized by reverse Monte Carlo modelling based on neutron/synchrotron X-ray diffraction and EXAFS data, supplemented by Raman and NMR spectroscopy. In vanadium-rich glass, the water durability, thermal stability and hardness improve as the amount of P 2 o 5 increases, and the network former of the glass changes from VO x polyhedra to the interplay between VO x polyhedra and po 4 tetrahedra. We find for the first time that the coordination number of oxygen atoms around a V 4+ is four, which is an unusually small coordination number, and plays an important role for water durability, thermal stability and hardness. Furthermore, we show that the similarity between glass and crystal beyond the nearest neighbour distance is important for glass properties. These results demonstrate that controlling the oxygen coordination and valence of the network-forming cation is necessary for designing the properties of glass. Oxide glass components are basically classified into network formers, network modifiers and intermediates by Zachariasen 1 and Sun 2. Typical network formers satisfy Zachariasen's rules 1 , but V 2 O 5 is classified as a network former 1 or intermediate 3. This is because it is hard for this oxide to form glass on its own because the oxygen coordination number is five in a crystalline phase, which is larger than the coordination number of typical network formers of three and four. V 2 O 5 based glasses have been widely studied for decades because V 2 O 5 glass is a typical semiconducting glass originating from hopping conduction. Indeed, not only fundamental research on electrical properties 4-8 but also applied research on cathode materials for lithium, sodium and magnesium ion batteries have been reported 9-12. This glass also has a low glass transition temperature and relatively low thermal expansion 4. These are quite attractive properties for low-melting glass used for sealing. In this field, lead borate glass with a high percentage of PbO has been applied to sealing below 400 °C in electronic devices, such as IC ceramic packages, crystal oscillators and micro-electro-mechanical systems. Since lead components are a hazardous substance for human health and the environment, it is necessary to avoid the use of PbO, and hence, V 2 O 5 based glass is a promising material for overcoming this problem 13-19. However, there are two critical problems that face the practical application of V 2 O 5 based glass: poor water durability and low thermal stability.
A Raman heterodyne detection of magnetic resonance has been performed for probing the local struc... more A Raman heterodyne detection of magnetic resonance has been performed for probing the local structure of a sodium phosphate glass doped with trivalent europium. High resolution rf modulation spectra between 0.5 and 10 MHz were observed without the laser field in resonance with electronic transitions of the glass. The intensity of the observed Raman heterodyne signal depends on the external static magnetic field and sample temperature as well as the intensity of the laser and rf fields. The ability of monitoring the rf resonance spectra with micrometer spatial resolution may offer a potentially important means to probe the variation of local structure in disordered solid state materials.
n h e submitted manuscriDt has been created bv thei University of Chicago as 'Operator of Argonne... more n h e submitted manuscriDt has been created bv thei University of Chicago as 'Operator of Argonne National Laboratory ('Argonne") under Contract No. W-31-109-ENG-38 with the U S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, non exclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracj, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
The small and wide angle neutron scattering instrument (TAIKAN) is designed to cover the wide q r... more The small and wide angle neutron scattering instrument (TAIKAN) is designed to cover the wide q range of 0.0005<q<20Å-1 using neutrons with the wavelength range of 0.5<<7.8Å and five detector banks which are small-, middle-, high-, ultra-small-angle, and backward detector banks. In this paper, the status of detector installation and data reduction method are presented. In addition, the instrument performance on the wide q-range measurement with high q-resolution is discussed with experimental results of two standard samples, a glassy carbon and a silver behenate.
, E-mail hans.te.nijenhuis@ panalytical.com Recent interest in nanomaterials has increased the ne... more , E-mail hans.te.nijenhuis@ panalytical.com Recent interest in nanomaterials has increased the need to analyze structures on a local (nano) scale. However, the atomic structures of nanoparticles and nanostructured materials are not accessible by conventional methods used to study crystalline materials, because of the short ordering range in these materials. One of the most promising techniques to study nanostructures using X-ray diffraction is total scattering pair distribution function (PDF) analysis. This technique is successfully applied in a number of application areas in materials science and technology. The PDF analysis technique makes use of high quality, high energy X-ray scattering data, usually obtained at synchrotron facilities, available in several national and international research centers around the world. Despite the advantages and data quality that measurements at synchrotron beam lines offer to the researcher, in practice it can be difficult and time-consuming to get access to the facilities required. In order to be prepared as good as possible and to make optimal use of the valuable experiment time offered, it is highly desirable to perform selective measurements on candidate samples in the own research laboratory. New developments in XRD technology have been directed towards the possibility of performing nanocrystallography experiments on a standard laboratory X-ray diffraction system. In this presentation we will report on the possibilities and limitations of the use of high-energy X-rays on a homelab system.
4SEASONS is a Fermi chopper spectrometer in operation at the Materials and Life Science Experimen... more 4SEASONS is a Fermi chopper spectrometer in operation at the Materials and Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC). 4SEASONS is expected to facilitate highefficiency measurements of weak inelastic signals on novel spin and lattice dynamics using thermal neutrons. The spectrometer is equipped with a coupled moderator and sophisticated components such as an elliptical converging neutron guide with high-critical-angle supermirrors, long (2.5 m) position-sensitive detectors, and a Fermi chopper appropriate for multiple-incident-energy (multi-E i) measurements by the repetition-rate multiplication technique. Herein, we discuss in detail the design and performance of the spectrometer, and present some examples of the measurements obtained using this spectrometer.
The three-dimensional atomic configuration of amorphous Ge 2 Sb 2 Te 5 and GeTe were derived by r... more The three-dimensional atomic configuration of amorphous Ge 2 Sb 2 Te 5 and GeTe were derived by reverse Monte Carlo simulation with synchrotron-radiation x-ray diffraction data. The authors found that amorphous Ge 2 Sb 2 Te 5 can be regarded as "even-numbered ring structure," because the ring statistics is dominated by four-and six-fold rings analogous to the crystal phase. On the other hand, the formation of Ge-Ge homopolar bonds in amorphous GeTe constructs both odd-and even-numbered rings. They believe that the unusual ring statistics of amorphous Ge 2 Sb 2 Te 5 is the key for the fast crystallization speed of the material.
Lead-indium phosphate glasses exhibit a number of useful properties such as a high indexof-refrac... more Lead-indium phosphate glasses exhibit a number of useful properties such as a high indexof-refraction, low preparation temperature and melt viscosity, and good chemical durability. The structure of such a glass (composition in wt. %: 65 PbO, 29 P2O5, 6 In2O3) has been investigated by total neutron scattering usin5 the GLAD diffractometer at Argonne's spallation neutron source IPNS. Peaks corresponding to the P-0, Pb-Ofin-0, and 0-0 pairs were observed in the radial distribution function. The short-range structure in the glass, in terms of average coordination numbers and bond distances, is compared with those of a pure P.705 glass and with the crystal structure of lead pyrophosphate, Pb2P207. Unlike silicate glasses in which the Si04 tetrahedra form a 3-dimensional network, the PO4 tetrahedra in phosphate glasses form a chain-like structure. The structural modification by the lead cations in phosphate glasses appears to occur mainly in the medium range-affecting the lengths and connectivity of the chain-like structure.
Previous x-ray diffraction measurements revealed the pressure-induced decomposition of an fcc-LaH... more Previous x-ray diffraction measurements revealed the pressure-induced decomposition of an fcc-LaH 2.3 into H-rich and H-poor fcc phases around 11 GPa. The present neutron diffraction measurements on LaD 2 confirm the formation of NaCl-type LaD as a counterpart of the D-rich LaD 2+δ by disproportionation. First-principle enthalpy and lattice dynamic calculations demonstrate that the NaCl-type LaH is stabilized at high pressures and can be recovered at ambient conditions. Finding the NaCl-type LaH will pave the way for investigations on the site-dependent nature of hydrogen-metal interactions.
Physics and Chemistry of Glasses-european Journal of Glass Science and Technology Part B, Dec 12, 2020
The use of high‑energy x‑ray diffraction techniques with the latest generation synchrotron source... more The use of high‑energy x‑ray diffraction techniques with the latest generation synchrotron sources has created new approaches to study quantitatively the structure of noncrystalline materials. Recently, this technique has been combined with neutron diffraction at pulsed source to provide more detailed and reliable structural information not previously available. This article reviews and summarises recent results obtained from the high energy x‑ray diffraction on several oxide glasses, SiO2, B2O3 and PbSiO3, using bending magnet beamlines at SPring‑8. In particular, it addresses the structural models of the oxide glasses obtained by the reverse Monte Carlo (RMC) modelling technique using both the high energy x‑ray and neutron diffraction data.
On April 2015, the J-PARC E56 (JSNS2: J-PARC Sterile Neutrino Search using neutrinos from J-PARC ... more On April 2015, the J-PARC E56 (JSNS2: J-PARC Sterile Neutrino Search using neutrinos from J-PARC Spallation Neutron Source) experiment officially obtained stage-1 approval from J-PARC. We have since started to perform liquid scintillator R&D for improving energy resolution and fast neutron rejection. Also, we are studying Avalanche Photo-Diodes (SiPM) inside the liquid scintillator. In addition to the R&D work, a background measurement for the proton beam bunch timing using a small liquid scintillator volume was planned, and the safety discussions for the measurement have been done. This report describes the status of the R&D work and the background measurements, in addition to the milestones required before stage-2 approval.
Understanding the structure-property relationship of glass material is still challenging due to a... more Understanding the structure-property relationship of glass material is still challenging due to a lack of periodicity in disordered materials. Here, we report the properties and atomic structure of vanadium phosphate glasses characterized by reverse Monte Carlo modelling based on neutron/synchrotron X-ray diffraction and EXAFS data, supplemented by Raman and NMR spectroscopy. In vanadium-rich glass, the water durability, thermal stability and hardness improve as the amount of P 2 o 5 increases, and the network former of the glass changes from VO x polyhedra to the interplay between VO x polyhedra and po 4 tetrahedra. We find for the first time that the coordination number of oxygen atoms around a V 4+ is four, which is an unusually small coordination number, and plays an important role for water durability, thermal stability and hardness. Furthermore, we show that the similarity between glass and crystal beyond the nearest neighbour distance is important for glass properties. These results demonstrate that controlling the oxygen coordination and valence of the network-forming cation is necessary for designing the properties of glass. Oxide glass components are basically classified into network formers, network modifiers and intermediates by Zachariasen 1 and Sun 2. Typical network formers satisfy Zachariasen's rules 1 , but V 2 O 5 is classified as a network former 1 or intermediate 3. This is because it is hard for this oxide to form glass on its own because the oxygen coordination number is five in a crystalline phase, which is larger than the coordination number of typical network formers of three and four. V 2 O 5 based glasses have been widely studied for decades because V 2 O 5 glass is a typical semiconducting glass originating from hopping conduction. Indeed, not only fundamental research on electrical properties 4-8 but also applied research on cathode materials for lithium, sodium and magnesium ion batteries have been reported 9-12. This glass also has a low glass transition temperature and relatively low thermal expansion 4. These are quite attractive properties for low-melting glass used for sealing. In this field, lead borate glass with a high percentage of PbO has been applied to sealing below 400 °C in electronic devices, such as IC ceramic packages, crystal oscillators and micro-electro-mechanical systems. Since lead components are a hazardous substance for human health and the environment, it is necessary to avoid the use of PbO, and hence, V 2 O 5 based glass is a promising material for overcoming this problem 13-19. However, there are two critical problems that face the practical application of V 2 O 5 based glass: poor water durability and low thermal stability.
A Raman heterodyne detection of magnetic resonance has been performed for probing the local struc... more A Raman heterodyne detection of magnetic resonance has been performed for probing the local structure of a sodium phosphate glass doped with trivalent europium. High resolution rf modulation spectra between 0.5 and 10 MHz were observed without the laser field in resonance with electronic transitions of the glass. The intensity of the observed Raman heterodyne signal depends on the external static magnetic field and sample temperature as well as the intensity of the laser and rf fields. The ability of monitoring the rf resonance spectra with micrometer spatial resolution may offer a potentially important means to probe the variation of local structure in disordered solid state materials.
n h e submitted manuscriDt has been created bv thei University of Chicago as 'Operator of Argonne... more n h e submitted manuscriDt has been created bv thei University of Chicago as 'Operator of Argonne National Laboratory ('Argonne") under Contract No. W-31-109-ENG-38 with the U S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, non exclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracj, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
The small and wide angle neutron scattering instrument (TAIKAN) is designed to cover the wide q r... more The small and wide angle neutron scattering instrument (TAIKAN) is designed to cover the wide q range of 0.0005<q<20Å-1 using neutrons with the wavelength range of 0.5<<7.8Å and five detector banks which are small-, middle-, high-, ultra-small-angle, and backward detector banks. In this paper, the status of detector installation and data reduction method are presented. In addition, the instrument performance on the wide q-range measurement with high q-resolution is discussed with experimental results of two standard samples, a glassy carbon and a silver behenate.
, E-mail hans.te.nijenhuis@ panalytical.com Recent interest in nanomaterials has increased the ne... more , E-mail hans.te.nijenhuis@ panalytical.com Recent interest in nanomaterials has increased the need to analyze structures on a local (nano) scale. However, the atomic structures of nanoparticles and nanostructured materials are not accessible by conventional methods used to study crystalline materials, because of the short ordering range in these materials. One of the most promising techniques to study nanostructures using X-ray diffraction is total scattering pair distribution function (PDF) analysis. This technique is successfully applied in a number of application areas in materials science and technology. The PDF analysis technique makes use of high quality, high energy X-ray scattering data, usually obtained at synchrotron facilities, available in several national and international research centers around the world. Despite the advantages and data quality that measurements at synchrotron beam lines offer to the researcher, in practice it can be difficult and time-consuming to get access to the facilities required. In order to be prepared as good as possible and to make optimal use of the valuable experiment time offered, it is highly desirable to perform selective measurements on candidate samples in the own research laboratory. New developments in XRD technology have been directed towards the possibility of performing nanocrystallography experiments on a standard laboratory X-ray diffraction system. In this presentation we will report on the possibilities and limitations of the use of high-energy X-rays on a homelab system.
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