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Journal Articles

Transverse asymmetry of $$gamma$$ rays from neutron-induced compound states of $$^{140}$$La

Yamamoto, Tomoki*; Okudaira, Takuya; Endo, Shunsuke; Fujioka, Hiroyuki*; Hirota, Katsuya*; Ino, Takashi*; Ishizaki, Kohei*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; et al.

Physical Review C, 101(6), p.064624_1 - 064624_8, 2020/06

 Times Cited Count:9 Percentile:73.66(Physics, Nuclear)

Journal Articles

Measurement of the angular distribution of $$gamma$$-rays after neutron capture by $$^{139}$$La for a T-violation search

Okudaira, Takuya; Shimizu, Hirohiko*; Kitaguchi, Masaaki*; Hirota, Katsuya*; Haddock, C. C.*; Ito, Ikuya*; Yamamoto, Tomoki*; Endo, Shunsuke*; Ishizaki, Kohei*; Sato, Takumi*; et al.

EPJ Web of Conferences, 219, p.09001_1 - 09001_6, 2019/12

Parity violating effects enhanced by up to 10$$^6$$ times have been observed in several neutron induced compound nuclei. There is a theoretical prediction that time reversal (T) violating effects can also be enhanced in these nuclei implying that T-violation can be searched for by making very sensitive measurements. However, the enhancement factor has not yet been measured in all nuclei. The angular distribution of the (n,$$gamma$$) reaction was measured with $$^{139}$$La by using a germanium detector assembly at J-PARC, and the enhancement factor was obtained. From the result, the measurement time to achieve the most sensitive T-violation search was estimated as 1.4 days, and a 40% polarized $$^{139}$$La target and a 70% polarized $$^3$$He spin filter whose thickness is 70 atm$$cdot$$cm are needed. Therefore high quality $$^3$$He spin filter is developed in JAEA. The measurement result of the (n,$$gamma$$) reaction at J-PARC and the development status of the $$^3$$He spin filter will be presented.

Journal Articles

Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment

Ino, Kohei*; Hernsdorf, A. W.*; Konno, Yuta*; Kozuka, Mariko*; Yanagawa, Katsunori*; Kato, Shingo*; Sunamura, Michinari*; Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; et al.

ISME Journal, 12(1), p.31 - 47, 2018/01

 Times Cited Count:49 Percentile:91.33(Ecology)

In this study, we found the dominance ofanaerobic methane-oxidizing archaea in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.

Journal Articles

Three-dimensional electronic structures and the metal-insulator transition in Ruddlesden-Popper iridates

Yamasaki, Atsushi*; Fujiwara, Hidenori*; Tachibana, Shoichi*; Iwasaki, Daisuke*; Higashino, Yuji*; Yoshimi, Chiaki*; Nakagawa, Koya*; Nakatani, Yasuhiro*; Yamagami, Kohei*; Aratani, Hidekazu*; et al.

Physical Review B, 94(11), p.115103_1 - 115103_10, 2016/11

AA2016-0587.pdf:2.55MB

 Times Cited Count:17 Percentile:61.21(Materials Science, Multidisciplinary)

In this study, we systematically investigate three-dimensional(3D) momentum-resolved electronic structures of Ruddlesden-Popper-type iridium oxides Sr$$_{n+1}$$Ir$$_{n}$$O$$_{3n+1}$$ using soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES). Our results provide direct evidence of an insulator-to-metal transition that occurs upon increasing the dimensionality of the IrO$$_{2}$$-plane structure. This transition occurs when the spin-orbit-coupled $$j_{eff}$$ = 1/2 band changes its behavior in the dispersion relation and moves across the Fermi energy. By scanning the photon energy over 350 eV, we reveal the 3D Fermi surface in SrIrO$$_{3}$$ and $$k_{z}$$-dependent oscillations of photoelectron intensity in Sr$$_{3}$$Ir$$_{2}$$O$$_{7}$$. To corroborate the physics deduced using low-energy ARPES studies, we propose to utilize SX-ARPES as a powerful complementary technique, as this method surveys more than one whole Brillouin zone and provides a panoramic view of electronic structures.

Journal Articles

Deep microbial life in high-quality granitic groundwater from geochemically and geographically distinct underground boreholes

Ino, Kohei*; Konno, Yuta*; Kozuka, Mariko*; Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Komatsu, Daisuke*; Tsunogai, Urumu*; Tanabe, Akifumi*; Yamamoto, Satoshi*; et al.

Environmental Microbiology Reports (Internet), 8(2), p.285 - 294, 2016/04

 Times Cited Count:26 Percentile:68.59(Environmental Sciences)

To understand the subsurface biosphere, borehole investigation was conducted for 300-m deep granitic rocks at the Mizunami underground research laboratory, Japan. The initial biomass was the highest with the flourish of aerobic H$$_{2}$$-oxidizing Hydrogenophaga spp., whereas an uncultivated lineage of the phylum Nitrospirae became predominant after three years with decreasing biomass. The common occurrence of many species of Nitrospirae and Chlorobi phyla at the geographically distinct sites and the exclusive detection of their phylogenetically related environmental sequences from deep groundwaters and terrestrial hot springs, suggest that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.

Journal Articles

High spatial resolution ZnO scintillator for an in situ imaging device in EUV region

Arita, Ren*; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Empizo, M.*; Hori, Tatsuhiro*; Fukuda, Kazuhito*; Minami, Yuki*; Sarukura, Nobuhiko*; Maruyama, Momoko; et al.

Optical Materials, 36(12), p.2012 - 2015, 2014/10

 Times Cited Count:9 Percentile:45.71(Materials Science, Multidisciplinary)

A single shot image of a ZnO crystal excited by the EUV laser of Kansai Photon Science Institute was captured. The evaluated EUV beam waist radii from the ZnO emission pattern along the horizontal and vertical axes are 5.0 and 4.7$$mu$$m, respectively. The expected focal spot size of EUV laser and the spatial resolution of the magnifier (including the Schwarzschild objectives and lenses) are however 1 and 4$$mu$$m, respectively. The discrepancy on the spatial resolutions is attributed to exciton diffusion. We estimated the ZnO exciton diffusion length from the effective decay time which is shortened by exciton-exciton collision quenching and which is dependence on excitation energy density. Our results indicate that the short lifetime of ZnO is required to improve the spatial resolution.

Journal Articles

The Effects of alloying and segregation for the reactivity and diffusion of oxygen on Cu$$_{3}$$Au(111)

Oka, Kohei*; Tsuda, Yasutaka*; Makino, Takamasa*; Okada, Michio*; Hashinokuchi, Michihiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Hideaki*

Physical Chemistry Chemical Physics, 16(36), p.19702 - 19711, 2014/08

 Times Cited Count:11 Percentile:40.33(Chemistry, Physical)

Journal Articles

Initial stages of Cu$$_{3}$$Au(111) oxidation; Oxygen induced Cu segregation and the protective Au layer profile

Tsuda, Yasutaka*; Oka, Kohei*; Makino, Takamasa*; Okada, Michio*; Di$~n$o, W. A.*; Hashinokuchi, Michihiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Hideaki*

Physical Chemistry Chemical Physics, 16(8), p.3815 - 3822, 2014/02

 Times Cited Count:14 Percentile:49(Chemistry, Physical)

Journal Articles

Evaluation of soft X-ray laser with ${it in situ}$ imaging device of high spatial resolution ZnO scintillator

Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Takeda, Kohei*; Nishi, Ryosuke*; Minami, Yuki*; Cadatal-Raduban, M.*; Sarukura, Nobuhiko*; Nishimura, Hiroaki*; et al.

Japanese Journal of Applied Physics, 50(12), p.122202_1 - 122202_4, 2011/12

 Times Cited Count:9 Percentile:38.03(Physics, Applied)

We demonstrate the potential of a hydrothermal method-grown ZnO as a high-spatial resolution imaging device for in-situ soft X-ray laser diagnostics by characterizing the exciton emission patterns. By plotting the emission pattern radii at each position, we estimated the evolution of the beam radius around the focal point. The beam profile of the Ni-like Ag ion plasma laser was estimated from the waist radii as 29 and 21$$mu$$m, the divergence angle as 7.2 and 11 mrad and the M2 factor as 47 and 50 in the horizontal- and vertical-axis, respectively. Spatial resolution of the magnifier was estimated to be 6$$mu$$m and is expected to improve by optimizing the optics of the magnifier and using a telescope. Our results would enhance the use of ZnO as an imaging device that would play a crucial role in the development and application of soft X-ray light sources.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:184 Percentile:99.44(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:8 Percentile:49.7(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2009 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Ichige, Satoru; Kurimoto, Yoshitaka; Hoshino, Seiichi; Akagi, Yosuke; Sato, Nobuyuki; Murakami, Hiroshi*; et al.

JAEA-Research 2011-002, 82 Pages, 2011/03

JAEA-Research-2011-002.pdf:5.64MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H20 (2008) Japanese fiscal year, which are (1) evaluation of long-term mechanical stability in the near-field including development of a creep mode of rock and analyses of mechanical behavior of TRU waste repository, (2) performance assessment of the disposal system including data acquisition and preparation on radionuclides migration, cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (3) alternative technology development including decomposition of nitrate.

Journal Articles

Evaluation of ZnO fast scintillator spatial resolution using the FZP-focused X-ray laser

Tanaka, Momoko; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Sarukura, Nobuhiko*; Nishikino, Masaharu; Oba, Toshiyuki; Kaihori, Takeshi; Ochi, Yoshihiro; et al.

JAEA-Conf 2011-001, p.126 - 128, 2011/03

The spatial resolution of hydrothermal method grown zinc oxide (ZnO) scintillator was evaluated using X-ray laser focused with Fresnel zone plate. The fluorescence image of the ZnO scintillator was measured to be less than 10um using CCD camera coupled with a Schbartzchild expander mirror. The availability of large size ZnO crystal up to 3-inch is quite attractive for future lithography and imaging applications.

Journal Articles

X-ray imaging by using ZnO crystal

Sarukura, Nobuhiko*; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Ehrentraut, D.*; Fukuda, Tsuguo*; Tanaka, Momoko; Nishikino, Masaharu; Kawachi, Tetsuya

Reza Kenkyu, 39(3), p.193 - 196, 2011/03

Development of light sources in the soft X-ray/X-ray region, such as laser induced plasma emission and XFEL, is in demand for applications in various fields of science, medicine, and industry, among others. To promote this endeavor, development of imaging devices as diagnostic tools in this wavelength region is required. ZnO is a prominent candidate material for high spatial and temporal resolution imaging devices because of its emission at 380 nm, lifetime of less than 1 ns, and availability of large and cheap but high quality crystals. We obtained a single shot image of ZnO emission pattern excited by an X-ray laser at the Advanced Photon Research Center, Japan Atomic Energy Agency. The spatial resolution was estimated to be around 10 $$mu$$m. This result shows that ZnO can be used as a powerful imaging device for applications such as EUV lithography.

Journal Articles

Simple orchestration application framework to control integrated simulations on grid

Tatekawa, Takayuki; Nakajima, Kohei*; Kim, G.; Kino, Chiaki; Teshima, Naoya; Suzuki, Yoshio; Takemiya, Hiroshi

FUJITSU Famirikai Rombunshu (Internet), 19 Pages, 2010/03

We have introduced about the framework to make the integration of large and complicated simulation such as a proof strength simulation of nuclear power plants and a control simulation of nuclear fusion plasma which codes are installed to distributed computers. We able to carry out detailed simulations by integrating various simulation methods with development of simulation technique. However it becomes a burden to control the integration of each simulation code for researchers. We have noticed that the execution scenarios of each code in cooperated simulation are roughly categorized to workflow type, pipeline type, and conditional branch type. Then we have developed the framework in which just write those patterns in a configuration file and achieve the cooperative execution of element codes without substantial modification of simulation codes.

Journal Articles

Research and development of fusion grid infrastructure based on Atomic Energy Grid InfraStructure (AEGIS)

Suzuki, Yoshio; Nakajima, Kohei; Kushida, Noriyuki; Kino, Chiaki; Aoyagi, Tetsuo; Nakajima, Norihiro; Iba, Katsuyuki*; Hayashi, Nobuhiko; Ozeki, Takahisa; Totsuka, Toshiyuki; et al.

Fusion Engineering and Design, 83(2-3), p.511 - 515, 2008/04

 Times Cited Count:3 Percentile:23.55(Nuclear Science & Technology)

In collaboration with the Naka Fusion Institute of Japan Atomic Energy Agency (NFI/JAEA) and the National Institute for Fusion Science of National Institute of Natural Science (NIFS/NINS), Center for Computational Science and E-systems of Japan Atomic Energy Agency (CCSE/JAEA) aims at establishing an integrated framework for experiments and analyses in nuclear fusion research based on the Atomic Energy Grid InfraStructure (AEGIS). AEGIS has been being developed by CCSE/JAEA aiming at providing the infrastructure that enables atomic energy researchers in remote locations to carry out R&D efficiently and collaboratively through the Internet. Toward establishing the integrated framework, we have been applying AEGIS to pre-existing three systems.

Journal Articles

"Crystal lattice engineering", an approach to engineer protein crystal contacts by creating intermolecular symmetry; Crystallization and structure determination of a mutant human RNase 1 with a hydrophobic interface of leucines

Yamada, Hidenori*; Tamada, Taro; Kosaka, Megumi*; Miyata, Kohei*; Fujiki, Shinya*; Tano, Masaru*; Moriya, Masayuki*; Yamanishi, Mamoru*; Honjo, Eijiro; Tada, Horiko*; et al.

Protein Science, 16(7), p.1389 - 1397, 2007/07

 Times Cited Count:39 Percentile:59.61(Biochemistry & Molecular Biology)

In an attempt to control protein incorporation in a crystal lattice, a leucine zipper-like hydrophobic interface (comprising four leucine residues) was introduced into a helical region (helix 2) of the human pancreatic ribonuclease 1 (RNase 1) that was predicted to form a suitable crystallization interface. Although crystallization of wild type RNase 1 has not yet been reported, the RNase 1 mutant having four leucines (4L-RNase 1) was successfully crystallized under several different conditions. The crystal structures were subsequently determined by X-ray crystallography by molecular replacement using the structure of bovine RNase A. The overall structure of 4L-RNase 1 is quite similar to that of the bovine RNase A, and the introduced leucine residues formed the designed crystal interface. To further characterize the role of the introduced leucine residues in crystallization of RNase 1, the number of leucines was reduced to three or two (3L- and 2L-RNase 1, respectively). Both mutants crystallized and a similar hydrophobic interface as in 4L-RNase 1 was observed. A related approach to engineer crystal contacts at helix 3 of RNase 1 (N4L-RNase 1) was also evaluated. N4L-RNase 1 also successfully crystallized, and formed the expected hydrophobic packing interface. These results suggest that appropriate introduction of a leucine zipper-like hydrophobic interface can promote intra molecular symmetry for more efficient protein crystallization in crystal lattice engineering efforts.

Oral presentation

Computational science and engineering for simulation and data processing in nuclear science and engineering

Hirayama, Toshio; Nakajima, Norihiro; Suzuki, Yoshio; Kino, Chiaki; Akutsu, Taku; Teshima, Naoya; Nakajima, Kohei

no journal, , 

Using computational technology in nuclear science and engineering, itself is meaningful and it is a good help for theoretical research as is experimental research and development. For 2007's exhibition in the International Conference for High Performance Computing, Storage, Networking and Analysis, AEGIS as grid computing, PST as Parallel visualization, CDAS for data mining are demonstrated. For simulation tipics, FIESTA as vibrational and structural analysis, material simulation for metal rusting, and bio-informatics as BAAQ for genom data searching are revealed. As French-Japanese research collaboration hosting by JST, matric solving technique are demonstrated.

Oral presentation

Single-shot focal spot image of EUV laser using a ZnO scintillator

Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Takatori, Satoru*; Estacio, E.*; Cadatal, M.*; Sarukura, Nobuhiko*; Nishimura, Hiroaki*; Mima, Kunioki*; Tanaka, Momoko; et al.

no journal, , 

We have observed the single shot, focused image of a EUV laser through the emission of a ZnO scintillator. An estimated EUV laser focal spot size of 50$$times$$88 micrometer is reasonable considering the long focal length of the spherical mirror. This work reports a feasible method to perform single-shot beam diagnostics for EUV laser sources using a ZnO crystal scintillator. Furthermore, since the ZnO fluorescence is at 380 nm wavelength, the imaging optics for the diagnostics can all be placed outside the vacuum chamber; thereby making experiments less cumbersome. Having a capability in fast and efficient beam profiling of EUV laser sources with acceptable resolving power is very important in future lithography applications.

Oral presentation

Improvement of SiC-MOS devices with plasma nitridation and AlON/SiO$$_{2}$$ stacked dielectrics

Watanabe, Heiji*; Kagei, Yusuke*; Kosono, Kohei*; Kirino, Takashi*; Watanabe, Yu*; Mitani, Shuhei*; Nakano, Yuki*; Nakamura, Takashi*; Yoshigoe, Akitaka; Teraoka, Yuden; et al.

no journal, , 

SiC-MOSFET's are expected for normally-off-type high performance power devices. Electrical defects due to residual inpurities such as carbon are in the interface of thermally-oxidized SiC-MOS's so that channel mobility is degraded preferentially. Although upgrade of reliability of a gate insulator is necessary for practical use, insulator degradation mechanisms have not well known yet. We are studying high quality MOS interface made by plasma nitridation techniques, upgrade of reliability and insulation by a stuck structure of a high-k insulator (AlON) layer and an SiO$$_{2}$$ underlayer. Recent research results on those subjects are reported in this talk.

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