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Oikawa, Kenichi; Takada, Hiroshi; Maekawa, Fujio; Harada, Masahide; Kai, Tetsuya; Sakai, Kenji; Futakawa, Masatoshi; Ikeda, Yujiro
no journal, ,
The neutron beam shutter system of JSNS, which has 23 beam ports, at J-PARC has a particular design that enable all the beam shutter to behave independently. This unique feature is realized by adoption of an electric servo motor system using compact ball screw jack. We have paid attention on workability of maintenance in a little space of a neighboring drive assemblies, barycenter of every shutter gate including its insert, and so on. We have carried out off-beam commissioning in middle 2007, and validated our design of shutter system in detail, including maintenance method.
Kai, Tetsuya; Kamiyama, Takashi*; Hiraga, Fujio*; Hirota, Katsuya*; Oi, Motoki; Maekawa, Fujio; Kato, Takashi; Kiyanagi, Yoshiaki*
no journal, ,
no abstracts in English
Maruyama, Ryuji; Yamazaki, Dai; Ebisawa, Toru*; Soyama, Kazuhiko
no journal, ,
Neutron supermirrors have been utilized as reflective optical devices at many neutron sources for transporting, focusing, polarizing neutron beam. In order to produce such devices for the new spallation neutron source (Japan Proton Accelerator Research Complex, J-PARC), an ion beam sputtering system with an effective deposition area of 0.2 m
has been installed in the Japan Atomic Energy Agency. The fabrication methods and the performance of the supermirrors are discussed.
Cu
Ge
NIikubo, Satoshi; Kodama, Katsuaki; Takenaka, Koshi*; Takagi, Hidenori*; Shamoto, Shinichi
no journal, ,
no abstracts in English
Takahashi, Nobuaki; Shibata, Kaoru; Sato, Taku*; Kawakita, Yukinobu*; Nakajima, Kenji; Arai, Masatoshi; Mamontov, E.*
no journal, ,
no abstracts in English
Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi
no journal, ,
We developed dynamic nuclear polarization (DNP) system for polarized small angle neutron scattering system in JAEA (SANS-J-II). The DNP system is composed of milliwave oscillator (94 GHz), cryostat (1 K), and superconducting magnet (3.5 Tesla). We succeeded in polarizing proton spins in polyetylene sample up to 63%, which exceeds the value reported elesewhere of 30
40%.
Fukazawa, Hiroshi
no journal, ,
Water molecules are dipolar, and neutron diffraction studies provide evidences that ices VIII and IX (the proton ordered phases of ices VII and III) exist as stable low-temperature phases at high pressure. However, under an atmospheric pressure, the proton of "normal" ice Ih is disordered even though a very low temperature. A question that has long fascinated researchers is whether there is an existence of ferroelectric water ice (FWI) named ice XI as a stable phase under an atmospheric pressure, which caused by aligned water molecules (i.e., the proton ordering). The old debate is implicated in our understanding of condensed matter, and recently the ferroelectricity in ice and clathrate hydrates (some hydrates also have the proton ordering) becomes an earnest subject: "FWI" exists on outer planets, such as Pluto ? On the basis of neutorn diffraction study, we discusse the structures of ices which form icy planets, such as Pluto and Charon.
Kikuchi, Takayuki; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Ishii, Yuya; Takeda, Masayasu; Kakurai, Kazuhisa; Sasaki, Yuji*; Kishimoto, Mikio*; Yokoyama, Makoto*; et al.
no journal, ,
no abstracts in English
Nakagawa, Hiroshi; Kataoka, Mikio
no journal, ,
Most globular proteins work in an aqueous milieu and water molecules located at the protein surface strongly affects the protein stability and function. Structure and dynamics of hydration water on protein were examined at various hydration levels to study hydration effect on protein dynamics. It was found that hydration dependent protein dynamical transition was observed at round 240 K, which is more significant above the threshold hydration level h = 0.30 (g water/g protein). At the low hydration level, hydration water is localized. On the other hand, at the higher hydration level the connectivity of the hydration water forms on the protein surface via hydrogen bond. The hydrogen bond network among the hydration water encircle the whole protein and the hydration water is percolated on the protein surface above the threshold hydration level. The protein dynamical transition is highly correlated with the percolation transition of the hydration water. At the percolation transition the translational dynamics of the hydration water markedly increase. The anomalous dynamical behavior of hydration water is coupled with the protein dynamics via hydrogen-bond network at protein-water interface. Such a dynamical coupling drives the hydration dependent protein dynamical transition.
and Xe gas in clathrate hydrateIgawa, Naoki; Taguchi, Tomitsugu; Fukazawa, Hiroshi; Yamauchi, Hiroki; Ishii, Yoshinobu*; Utsumi, Wataru
no journal, ,
The neutron diffractions of CO and Xe clathrate hydrates were measured using the HRPD. Obtained diffraction data were analyzed by the Rietveld method, and then Maximum Entropy Method was carried out to obtain the nuclear density maps. The details on the temperature dependence of motion behaviors of CO and Xe gas in the cages of clathrate hydrate will be discussed.
Shibata, Kaoru; Takahashi, Nobuaki; Sato, Taku*; Kawakita, Yukinobu*; Tsukushi, Itaru*; Nakagawa, Hiroshi; Fujiwara, Satoru; Nakajima, Kenji; Arai, Masatoshi
no journal, ,
no abstracts in English
Noda, Yohei; Kumada, Takayuki; Koizumi, Satoshi; Hashimoto, Takeji
no journal, ,
We polarized nuclear spins in hydrogen atoms of polyethylene samples doped with organic radical (TEMPO) by use of dynamic nuclear polarization (DNP), in which the sample was irradiated by millimeter wave (94 GHz) at 3.3 Tesla and 1.4 K. For the samples under the DNP state, we conducted small-angle scattering experiment with polarized neutrons. For low crystalline sample (polarization: 43%), the shift of the incoherent scattering level was observed. For highly crystalline sample (polarization: 26%), the enhancement of the coherent scattering due to the crystalline structure was observed.
Oku, Takayuki; Shinohara, Takenao; Kikuchi, Takayuki; Oba, Yojiro; Iwase, Hiroki; Koizumi, Satoshi; Suzuki, Junichi; Shimizu, Hirohiko
no journal, ,
no abstracts in English
Motokawa, Ryuhei; Koizumi, Satoshi; Hashimoto, Takeji; Iida, You*
no journal, ,
We constructed a focusing ultra-small-angle scattering spectrometer (SANS-J-II) at research reactor JRR3, Tokai, Japan. Focusing unlra-small-angle neutron scattering (USANS) and conventional small-angle neutron scattering (SANS) can observe the length scale about 1000 nm - 100 nm and 100 nm - 1 nm, respectively. Focusing USANS, thus realized, plays an important role to investigate the time-evolution of hierarchically ordered structures in the living radical polymerization solution, preparing poly(methyl methacrylate)-block-polystyrene. In the reaction process to synthesize PS block chains from the end of PMMA block chain, we found the interplay between macro and microdomain structures as follows. As the polymerization proceeds, (i) first by polymerization-induced disorder-order transition, a lamellar microdomain appears and (ii) second by order-order transitions, the morphologies of microdomains change to PMMA cylinder and successively to PMMA sphere.
Futakawa, Masatoshi
no journal, ,
no abstracts in English
Iwase, Hiroki; Koizumi, Satoshi; Hashimoto, Takeji; Yamaki, Tetsuya; Sawada, Shinichi; Maekawa, Yasunari
no journal, ,
By using ultra-small-angle neutron scattering (USANS) techniques, we have investigated the hierarchical structures of the crosslinked-polytetrafluoroethylene (PTFE) electrolyte membrane, which is made by using both radiation-crosslinking and radiation-induced grafting of styrene, in order to reveal the correlation between the hierarchical structure and a proton conducting mechanism. We observed structural changes of crosslinking PTFE electrolyte membrane in each synthetic process and compared the structures between the crosslinking PTFE electrolyte membrane and Nafion112 under swollen state. We detected each effects of radiation crosslinking and grafting, respectively on the scattering profiles. Scattering profile for swollen crosslinking PTFE electrolyte membrane in DO has a no peak around Q = 1.2 
, where scattering profile for Nafion has a peak reflected the ion-cluster structure. However, a shoulder-like profile is appeared clearly at Q = 0.14 . This peak-position is agreement with that observed in the scattering profile after radiation-crosslinking process. The presented results suggested that the structure formed by the radiation-crosslinking is close relation with the proton conductivity for the crosslinking PTFE electrolyte membrane.
Kurihara, Kazuo; Adachi, Motoyasu; Tamada, Taro; Ohara, Takashi; Kuroki, Ryota
no journal, ,
no abstracts in English
Harjo, S.; Moriai, Atsushi; Suzuya, Kentaro; Aizawa, Kazuya; Nakai, Tetsushi*; Shirakihara, Kaori*; Takata, Shinichi; Morii, Yukio; Arai, Masatoshi; Tomota, Yo*; et al.
no journal, ,
no abstracts in English
Shinohara, Takenao; Takata, Shinichi; Suzuki, Junichi; Oku, Takayuki; Suzuya, Kentaro; Aizawa, Kazuya; Otomo, Toshiya*; Sugiyama, Masaaki*; Arai, Masatoshi
no journal, ,
no abstracts in English
Yamaguchi, Daisuke; Mayama, Hiroyuki*; Koizumi, Satoshi; Tsujii, Kaoru*; Hashimoto, Takeji
no journal, ,
In this study, the structure of the "novel" porous silica specimens prepared by sol-gel method with alkylketene dimer (AKD) template was characterized on the length scale from nanometers to tens of microns by small-angle neutron scattering measurements. AKD is a kind of wax and has been proven to form a fractal structure by recrystallization. Due to the AKD template, the porous silica product exhibited a distinct mass-fractal structure, which persists over the length scale ten times larger than that of conventional silica aerogel. While on the other hand, the mass fractal dimension is similar between the silica aerogels and the specimen investigated in this study, suggesting that the space symmetry is somewhat similar between those two systems.