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Journal Articles

Inter-atomic force constants of BaF$$_{2}$$ by diffuse neutron scattering measurement

Sakuma, Takashi*; Makhsun*; Sakai, Ryutaro*; Xianglian*; Takahashi, Haruyuki*; Basar, K.*; Igawa, Naoki; Danilkin, S. A.*

AIP Conference Proceedings 1656, p.020002_1 - 020002_4, 2015/04

 Times Cited Count:1 Percentile:51.16

Diffuse neutron scattering measurement on BaF$$_{2}$$ crystals was performed at 10 K and 295 K. Oscillatory form in the diffuse scattering intensity of BaF$$_{2}$$ was observed at 295 K. The correlation effects among thermal displacements of F-F atoms were obtained from the analysis of oscillatory diffuse scattering intensity. From the values of correlation effects and Debye-Waller temperature parameters, force constants among the first and second nearest neighboring atoms of BaF$$_{2}$$, were determined to be 4.40 and 2.30 eV/$AA$^{2}$$ at 295 K, respectively

Journal Articles

Estimation of force constants of Al from diffuse neutron scattering measurement

Makhsun*; Hashimoto, Takuya*; Sakuma, Takashi*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki; Danilkin, S. A.*

Journal of the Physical Society of Japan, 83(7), p.074602_1 - 074602_4, 2014/07

 Times Cited Count:2 Percentile:23.05(Physics, Multidisciplinary)

The correlations of atomic thermal displacements in Al were obtained from the analysis of diffuse neutron scattering intensity. The interatomic force constants were determined from the correlation effects using a newly introduced equation. The derived force constants and the crystal structure of Al were used to estimate the phonon dispersion relations, phonon density of states, and specific heat by computer simulation. The calculated phonon dispersion relations and specific heat of Al are similar to those obtained from inelastic neutron scattering and specific heat measurements, respectively.

Journal Articles

Inter-atomic force constants of Ag$$_{2}$$O from diffuse neutron scattering measurement

Wada, Tamotsu*; Sakuma, Takashi*; Sakai, Ryutaro*; Uehara, Hiroyuki*; Xianglian*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki; Danilkin, S. A.*

Solid State Ionics, 225, p.18 - 21, 2012/10

 Times Cited Count:6 Percentile:31.07(Chemistry, Physical)

Diffuse neutron scattering measurement on Ag$$_{2}$$O crystals was performed at 8 K and 295 K. The observed diffuse scattering intensities were analyzed by including the correlation effects among thermal displacements of atoms in Ag$$_{2}$$O. Using the values of correlation effects among neighboring atoms and the values of Debye-Waller temperature parameter, force constants among first, second and third nearest neighboring atoms have been evaluated.

Journal Articles

Inter-atomic force constants from correlation effects among thermal displacement of atoms in PbTe

Xianglian*; Sakuma, Takashi*; Mohapatra, S. R.*; Uehara, Hiroyuki*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki

Molecular Simulation, 38(5), p.448 - 451, 2012/04

 Times Cited Count:1 Percentile:3.23(Chemistry, Physical)

Diffuse neutron scattering measurements have been performed on powder PbTe at 10 and 294 K. Oscillatory diffuse scattering intensity is clearly observed at 294 K. Oscillatory form of the diffuse neutron scattering intensity for PbTe was explained on inclusion of correlation effects among thermal displacements of atoms. From the values of correlation effects and Debye-Waller temperature parameter, force constants among the first nearest neighboring atoms was calculated, $$alpha$$ $$_{rm Pb-Te}$$ = 215 eV/nm$$^{2}$$, and the second ones were $$alpha$$ $$_{rm Pb-Pb}$$ =108 eV/nm$$^{2}$$ and $$alpha$$ $$_{rm Te-Te}$$ = 144 eV/nm$$^{2}$$ at 294 K.

Journal Articles

Quench detection of fast plasma events for the JT-60SA central solenoid

Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Kamiya, Koji; Takahashi, Yoshikazu; Yoshida, Kiyoshi

Fusion Engineering and Design, 87(1), p.23 - 29, 2012/01

 Times Cited Count:8 Percentile:58.08(Nuclear Science & Technology)

The JT-60 is planned to be modified to a full-superconducting tokamak. The maximum temperature of the magnet during its quench might reach the temperature of higher than several hundreds Kelvin that will damage the magnet itself. The high precision quench detection system, therefore, is important in the protection system. The disk-shaped pickup coils are inserted in the CS module for quench detection. Thus we improved the analysis model to evaluate the applicability of the disk-shaped pickup coils to quench detection system during the fast plasma event, such as disruption, by introducing the passive coil series such as vacuum vessel and stabilizer. The analysis results show that the disk-shaped pickup coil is applicable whenever the standard operation and fast plasma event. Additionally, the pickup coil design method is also modified to reduce the total cost of protection system. In this paper, the improved analysis method, modified design method and those results are described.

Journal Articles

Correlation effects among thermal displacements of atoms in KBr

Sakuma, Takashi*; Xianglian*; Shimizu, Norifumi*; Mohapatra, S. R.*; Isozaki, Nobuhiro*; Uehara, Hiroyuki*; Takahashi, Haruyuki*; Basar, K.*; Igawa, Naoki; Kamishima, Osamu*

Solid State Ionics, 192(1), p.54 - 57, 2011/06

 Times Cited Count:11 Percentile:48.1(Chemistry, Physical)

Diffuse neutron scattering measurements have been performed on powder KBr. The oscillatory scheme of the diffuse scattering intensity is explained by the values of correlation effects among thermal displacements of 1st, 2nd and 3rd nearest neighboring atoms which are almost the same as those in other ionic crystals. Force constants among 1st, 2nd and 3rd nearest neighboring atoms are obtained from the correlation effects at 90 K are 0.83 eV/$AA $^{2}$$, 0.50 eV/$AA $^{2}$$ and 0.41 eV/$AA $^{2}$$, respectively.

Journal Articles

X-ray and neutron protein crystallographic analysis of the trypsin-BPTI complex

Kawamura, Kenji*; Yamada, Taro*; Kurihara, Kazuo; Tamada, Taro; Kuroki, Ryota; Tanaka, Ichiro*; Takahashi, Haruyuki*; Niimura, Nobuo*

Acta Crystallographica Section D, 67(2), p.140 - 148, 2011/02

 Times Cited Count:23 Percentile:87.3(Biochemical Research Methods)

Journal Articles

Force constants of Cu crystals from diffuse neutron scattering measurement

Sakuma, Takashi*; Mohapatra, S. R.*; Uehara, Hiroyuki*; Sakai, Ryutaro*; Xianglian*; Takahashi, Haruyuki*; Igawa, Naoki; Basar, K.*

Atom Indonesia, 36(3), p.121 - 124, 2010/12

Diffuse neutron scattering measurement on Cu crystals was performed at 10 K and 300 K and the observed diffuse scattering intensities were analyzed by including the correlation effects among thermal displacements of atoms in the theory. Using the values of correlation effects among neighboring atoms and the values of Debye-Waller temperature parameter, force constants among first, second and third nearest neighboring atoms had been evaluated. The estimated values of force constants among first, second and third nearest neighboring atoms of Cu were 5.58, 3.63 and 2.37 eV/${AA}$ $$^{2}$$ at 300 K, respectively. The relation between correlation effects and the inter-atomic distance is not depending much on the crystal binding types.

Journal Articles

Diffuse neutron scattering calculation of spinel structure of LiMn$$_{2}$$O$$_{4}$$

Basar, K.*; Xianglian*; Sakuma, Takashi*; Takahashi, Haruyuki*; Abe, Osami*; Igawa, Naoki

AIP Conference Proceedings 1244, p.129 - 135, 2010/06

 Times Cited Count:0 Percentile:0.07

Neutron scattering experiment has been performed on powder LiMn$$_{2}$$O$$_{4}$$ with spinel structure at room temperature. The profile of diffuse scattering was analyzed including the correlation effects among thermal displacement of atoms Li-Li, Li-Mn, Li-O, Mn-Mn, Mn-O and O-O. It was found that the main contribution to the oscillatory profile of diffuse scattering intensity of LiMn$$_{2}$$O$$_{4}$$ was O-O pairs.

Journal Articles

Commissioning of the IFMIF/EVEDA accelerator prototype; Objectives & plans

Vermare, C.*; Garin, P.*; Shidara, H.*; Beauvais, P. Y.*; Mosnier, A.*; Ibarra, A.*; Heidinger, R.*; Facco, A.*; Pisent, A.*; Maebara, Sunao; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.777 - 779, 2010/05

Journal Articles

The Accelerator prototype of the IFMIF/EVEDA project

Mosnier, A.*; Beauvais, P. Y.*; Branas, B.*; Comunian, M.*; Facco, A.*; Garin, P.*; Gobin, R.*; Gournay, J. F.*; Heidinger, R.*; Ibarra, A.*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.588 - 590, 2010/05

Journal Articles

Diffuse scattering of $$gamma$$-PbF$$_{2}$$

Xianglian*; Sakuma, Takashi*; Basar, K.*; Takahashi, Haruyuki*; Igawa, Naoki

Journal of the Physical Society of Japan, 79(Suppl.A), p.29 - 32, 2010/03

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

$$gamma$$-PbF$$_{2}$$ belongs to cubic structure with disordered arrangements of F atoms and shows high ionic conductivity at high temperature. Neutron diffuse scattering intensity measurement has been performed at 773 K. Strong and oscillatory diffuse scattering intensity has been observed. The diffuse scattering can be explained by the correlation effects among thermal displacements of atoms and the short-range order in disordered arrangements of F atoms.

Journal Articles

Progress of the IFMIF/EVEDA prototype accelerator in the Broader Approach activities for fusion energy in FY2008

Shinto, Katsuhiro; Vermare, C.*; Asahara, Hiroo; Sugimoto, Masayoshi; Garin, P.*; Maebara, Sunao; Takahashi, Hiroki; Sakaki, Hironao; Kojima, Toshiyuki; Ohira, Shigeru; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.668 - 670, 2010/03

Progress of the IFMIF/EVEDA prototype accelerator in fiscal year of 2008 is described. All the sub-systems of the prototype accelerator have started to design, settled the plan of the manufacturing and component tests and fixed the design parameters. As a result of the analysis of planning for the engineering validation of the IFMIF accelerator system, the project duration to be prolonged to the end of 2014 including some months for contingency was approved by the BA Steering Committee. In this article, the design status of each accelerator component, the interface between the accelerator components and the IFMIF/EVEDA Accelerator Building settled in International Fusion Energy Research Centre (IFERC) in Rokkasho and the proposed accelerator commissioning plan for the engineering validation will be presented.

Journal Articles

Estimation of inter-atomic force constants and phonon dispersion using correlation effects among thermal displacement of atoms in Ge

Sakuma, Takashi*; Mohapatra, S. R.*; Isozaki, Nobuhiro*; Uehara, Hiroyuki*; Xianglian*; Basar, K.*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki

Journal of Non-Crystalline Solids, 357(2), p.559 - 562, 2010/01

 Times Cited Count:2 Percentile:18.17(Materials Science, Ceramics)

The oscillatory diffuse scattering intensity of Ge was observed by neutron scattering measurement. The force constants among the first, second and third nearest neighboring atoms in Ge were determined from the values of correlation effects and Debye-Waller temperature parameters. The inter-atomic force constants among the first, second and third nearest neighboring atoms at 80 K in Ge are 363 eV/nm$$^{2}$$, 232 eV/nm$$^{2}$$ and 200 eV/nm$$^{2}$$, respectively.

Journal Articles

Correlation effects among thermal displacements of atoms from diffuse neutron scattering measurements

Sakuma, Takashi*; Mohapatra, S. R.*; Yokokawa, Jo*; Shimizu, Norifumi*; Isozaki, Nobuhiro*; Uehara, Hiroyuki*; Xianglian*; Basar, K.*; Takahashi, Haruyuki*; Kamishima, Osamu*; et al.

Proceedings of 12th Asian Conference on Solid State Ionics and 15th Chinese Conference on Solid State Ionics, p.439 - 445, 2010/00

Diffuse neutron scattering intensities from ionic crystals, covalent crystals and metal crystals are analyzed by including the correlation effects among thermal displacements of atoms into the function describing background intensity. The obtained values of correlation effects among first nearest neighboring atoms are 0.7 near room temperature. The values of the correlation effects do not depend much on the type of the crystal binding near room temperature. The values of correlation effects decrease rapidly with the increase of inter-atomic distances. The correlation effects also decrease with the decrease of temperature.

Journal Articles

Correlation effects among thermal displacements of atoms in VSe by diffuse neutron scattering measurement

Sakuma, Takashi*; Xianglian*; Siagian, S.*; Basar, K.*; Takahashi, Haruyuki*; Igawa, Naoki; Kamishima, Osamu*

Journal of Thermal Analysis and Calorimetry, 99(1), p.173 - 176, 2009/10

 Times Cited Count:3 Percentile:14.32(Thermodynamics)

Neutron diffraction measurements have been performed on powder VSe at 294 K. The diffuse scattering theory including correlation effects among thermal displacements of atoms is applied to background function in the rietveld analysis. The oscillatory scheme of the diffuse scattering intensity from hexagonal VSe is explained by the correlation effects among far-neighboring Se-Se atoms. The values of the correlation effects depend on the inter-atomic distance and not on the crystal structure.

Journal Articles

Diffuse neutron scattering of KBr at room temperature and its application as background function in rietveld analysis

Basar, K.*; Xianglian*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki

ITB Journal of Science, 41A(1), p.50 - 58, 2009/05

Diffuse neutron scattering profile of KBr at room temperature was explained by including the correlation among thermal displacement of atoms up to third neighbor atom in the crystal KBr. The values of correlation effects decrease with inter-atomic distance. The diffuse scattering theory including correlation effects is applied as background function in Rietveld analysis.

Journal Articles

Inter-atomic distance and temperature dependence of correlation effects among thermal displacements

Xianglian*; Siagian, S.*; Basar, K.*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki; Ishii, Yoshinobu*

Solid State Ionics, 180(6-8), p.480 - 482, 2009/05

 Times Cited Count:3 Percentile:18.05(Chemistry, Physical)

Correlation effects among thermal vibrations of atoms are very important to realize the thermal properties of materials. We discuss the inter-atomic distance and temperature dependence of the correlation effects in ionic crystal, AgBr, CuBr, CuI and CuCl, by neutron diffraction method. From the Rietveld analysis of those diffraction data the lattice constants and Deby-Waller parameters were determined. The diffuse scattering of diffraction data was analyzed with the correlation effect, $$mu$$. It is found that the $$mu$$ is 0.6-0.75 for the inter-atomic distance around 2.5${AA}$ and 0.4-0.5 for 4${AA}$ for all ionic crystals. The value of $$mu$$ decreases with the decrease of temperature.

Journal Articles

Correlation effects among atomic thermal displacements in oscillatory diffuse neutron scattering of ZnSe

Basar, K.*; Siagian, S.*; Xianglian*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki

Nuclear Instruments and Methods in Physics Research A, 600(1), p.237 - 239, 2009/02

 Times Cited Count:9 Percentile:56.98(Instruments & Instrumentation)

Neutron scattering measurements have been performed on powder ZnSe at 15, 150 and 300 K. The oscillatory diffuse neutron scattering intensity is explained by including the correlation effects among atomic thermal displacement of the first, second and third nearest neighboring atoms. It was found that the values of correlation effects decrease by increasing inter-atomic distances and with the decrease of temperature.

Journal Articles

Anneal temperature effect on crystallite size and electric conductivity of LiMn$$_{2}$$O$$_{4}$$

Basar, K.*; Xianglian*; Siagian, S.*; Ohara, Kota*; Sakuma, Takashi*; Takahashi, Haruyuki*; Abe, Osami*; Igawa, Naoki; Ishii, Yoshinobu*

Indonesian Journal of Physics, 20(1), p.9 - 11, 2009/01

Nanosized LiMn$$_{2}$$O$$_{4}$$ has been successfully prepared by solid state reaction of LiOH and MnO$$_{2}$$. Neutron scattering experiments at room temperature and conductivity measurement have been performed on the samples. Anneal temperature effect on the crystallite size and electric conductivity of LiMn$$_{2}$$O$$_{4}$$ is analyzed. The average crystallite size is obtained from the full width at half maximum (FWHM) of Bragg lines using Scherrer equation. The average crystallite size increases with the increase of anneal temperature. Activation energy and conductivity prefactor increase with anneal temperature.

39 (Records 1-20 displayed on this page)