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Journal Articles

Micropores and mass transfer in the formation of myrmekites

Yuguchi, Takashi*; Yuasa, Haruka*; Izumino, Yuya*; Nakashima, Kazuo*; Sasao, Eiji; Nishiyama, Tadao*

American Mineralogist, 107(3), p.476 - 488, 2022/03

 Times Cited Count:1 Percentile:73.85(Geochemistry & Geophysics)

The methodology and interpretations in this study provide new insights into the mechanism of myrmekite formation in a granitic system. The presence of micropores in the myrmekites and this study clarified that the genesis of micropores is related to the formation of myrmekites in the Toki granite. The results led to an increased understanding of (1) an estimate of mass transfer between the reactant and product minerals, and the inflow and outflow of components with consideration of the volume change due to micropore formation, (2) the factor controlling the formation of micropores during myrmekitization, and (3) the sequential variations in the hydrothermal fluid chemistry during sub-solidus conditions. The micropores act as a migration pathway for hydrothermal fluid and thus enhance the mass transfer within a granitic body starting with the myrmekite formation and continuing through the present day and into the future.

Journal Articles

Association of hydrothermal plagioclase alteration with micropores in a granite; Petrographic indicators to evaluate the extent of hydrothermal alteration

Yuguchi, Takashi*; Izumino, Yuya*; Sasao, Eiji

Journal of Mineralogical and Petrological Sciences (Internet), 117(1), p.220415_1 - 220415_12, 2022/00

 Times Cited Count:0 Percentile:0.03(Mineralogy)

This study presents the use of petrographic plagioclase alteration indicators as a new method for quantitatively evaluating the extent of plagioclase alteration within granites, using the Toki granite, central Japan. Alteration indicators and areal fractions of microvoids in the plagioclases were obtained via BSE image analysis. The volume of the micropores in the altered plagioclase was characterized by the areal fraction of microvoids in the grains. The plagioclase alteration indicators were obtained as the ratio between the alteration product area and the original plagioclase area. In our previous study, we focused on biotite chloritization indicators. We found positive correlations between the plagioclase alteration and biotite chloritization indicators in the same sample, indicating that each alteration indicator can be used independently as a representative value for the sample. In the Toki granite, the plagioclase alteration was related to the biotite chloritization.

Journal Articles

Mass transfer associated with chloritization in the hydrothermal alteration process of granitic pluton

Yuguchi, Takashi*; Matsuki, Takanobu*; Izumino, Yuya*; Sasao, Eiji; Nishiyama, Tadao*

American Mineralogist, 106(7), p.1128 - 1142, 2021/07

 Times Cited Count:1 Percentile:30.91(Geochemistry & Geophysics)

This study reveals the hydrothermal alteration processes in a pluton, with a focus on the mass transfer between minerals and hydrothermal fluid. Hydrothermal alteration of the Toki granite in Tono area, central Japan, progressed through the successive processes of chloritization, plagioclase alteration, and precipitation of a carbonate mineral. This paper describes the alteration process of hornblende chloritization, K-feldspar chloritization, and the formation of fracture-filling chlorite through petrography and mineral chemistry. Several types of chloritization reactions (including biotite chloritization) can be characterized by their reaction with the inflow of Al$$^{3+}$$, Fe$$^{2+}$$, Mn$$^{2+}$$, and Mg$$^{2+}$$ and the outflow of H$$_{4}$$SiO$$_{4}$$, Ca$$^{2+}$$, K$$^{+}$$+, and F$$^{-}$$. The reactions of chloritization and plagioclase alteration represent the sequential variations in fluid chemistry at temporal conditions from 68 Ma to 51 Ma as the temperature decreased from 350$$^{circ}$$C to 180$$^{circ}$$C.

Journal Articles

Genesis and development processes of fractures in granite; Petrographic indicators of hydrothermal alteration

Yuguchi, Takashi*; Izumino, Yuya*; Sasao, Eiji

PLOS ONE (Internet), 16(5), p.e0251198_1 - e0251198_17, 2021/05

 Times Cited Count:1 Percentile:26.02(Multidisciplinary Sciences)

This study analyzes the relationships among alteration indicators, areal microvoid fractions in chloritized biotite, and macroscopic fracture frequencies in the Toki granite, central Japan, to establish the genesis and development processes of fractures in granite. Petrographic alteration indicators using biotite chloritization as innovative methods are proposed to evaluate the extent of hydrothermal alteration and fracture frequency within granites. Samples with high macroscopic fracture frequencies correspond to a high number of areal microvoid fractions and large alteration indicators. The alteration indicators contribute to the characterization of present and future distributions of macroscopic fracture frequencies.

Journal Articles

Radioactivity and radionuclides in deciduous teeth formed before the Fukushima-Daiichi Nuclear Power Plant accident

Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.

Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05

 Times Cited Count:4 Percentile:62.94(Multidisciplinary Sciences)

Journal Articles

Commissioning of Versatile Compact Neutron Diffractometer (VCND) at the B-3 beam port of Kyoto University Research Reactor (KUR)

Mori, Kazuhiro*; Okumura, Ryo*; Yoshino, Hirofumi*; Kanayama, Masaya*; Sato, Setsuo*; Oba, Yojiro; Iwase, Kenji*; Hiraka, Haruhiro*; Hino, Masahiro*; Sano, Tadafumi*; et al.

JPS Conference Proceedings (Internet), 33, p.011093_1 - 011093_6, 2021/03

no abstracts in English

Journal Articles

Study of neutron-nuclear spin correlation term with a polarized Xe target

Sakai, Kenji; Oku, Takayuki; Okudaira, Takuya; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kakurai, Kazuhisa*; Shimizu, Hirohiko*; Hirota, Katsuya*; et al.

JPS Conference Proceedings (Internet), 33, p.011116_1 - 011116_6, 2021/03

In neutron fundamental physics, study of correlation term $${bf s}cdot{bf I}$$ of a neutron spin $${bf s}$$ and a target nuclear spin $${bf I}$$ is important because $${bf s}cdot{bf I}$$ term interferes to parity non-conserving (PNC) and time reversal non-conserving terms. For this study, a xenon (Xe) is an interesting nucleus because it has been observed an enhancement of PNC effect around neutron resonance peaks, and polarizes up to $$ sim 10^{-1}$$ by using a spin exchange optical pumping (SEOP) method. We would plan to develop a polarized Xe gas target with a compact in-situ SEOP system, and to study $${bf s}cdot{bf I}$$ term by utilizing epithermal neutron beams supplied from a high intense pulsed spallation neutron source. As the first step, we attempted to measure neutron polarizing ability caused by $${bf s}cdot{bf I}$$ term at a 9.6 eV s-wave resonance peak of $$^{129}$$Xe at BL10 in MLF, by detecting change $$Delta R$$ of ratio between neutron transmissions with the polarized and unpolarized Xe target. After demonstrating that our apparatus could detect small change ($$Delta R_{rm DB} , {approx},10^{-2}$$) of neutron transmissions caused by Doppler broadening effect, a signified value of $$Delta R$$ has been obtained as preliminary results. For analyzing the obtained $$Delta R$$ in detail, we are improving our nuclear magnetic resonance and electron paramagnetic resonance systems for evaluating Xe polarization independently of neutron beams.

Journal Articles

Neutron Bragg-edge transmission imaging for microstructure and residual strain in induction hardened gears

Su, Y. H.; Oikawa, Kenichi; Shinohara, Takenao; Kai, Tetsuya; Horino, Takashi*; Idohara, Osamu*; Misaka, Yoshitaka*; Tomota, Yo*

Scientific Reports (Internet), 11, p.4155_1 - 4155_14, 2021/02

 Times Cited Count:6 Percentile:76.8(Multidisciplinary Sciences)

Journal Articles

Development of ${it spatiotemporal}$ measurement and analysis techniques in X-ray photoelectron spectroscopy; From NAP-HARPES to 4D-XPS

Toyoda, Satoshi*; Yamamoto, Tomoki*; Yoshimura, Masashi*; Sumida, Hirosuke*; Mineoi, Susumu*; Machida, Masatake*; Yoshigoe, Akitaka; Suzuki, Satoru*; Yokoyama, Kazushi*; Ohashi, Yuji*; et al.

Vacuum and Surface Science, 64(2), p.86 - 91, 2021/02

We have developed ${it spatiotemporal}$ measurement and analysis techniques in X-ray photoelectron spectroscopy. To begin with, time-division depth profiles of gate stacked film interfaces have been achieved by NAP-HARPES (Near Ambient Pressure Hard X-ray Angle-Resolved Photo Emission Spectroscopy) data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division ARPES data, which enables us to realize 4D-XPS analysis. It is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling in NAP-HARPES data is effective to perform dynamic measurement of depth profiles with high precision.

Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 Times Cited Count:7 Percentile:78.38(Instruments & Instrumentation)

Journal Articles

Release behavior of radionuclides from MOX fuels irradiated in a fast reactor during heating tests

Tanaka, Kosuke; Sato, Isamu*; Onishi, Takashi; Ishikawa, Takashi; Hirosawa, Takashi; Katsuyama, Kozo; Seino, Hiroshi; Ohno, Shuji; Hamada, Hirotsugu; Tokoro, Daishiro*; et al.

Journal of Nuclear Materials, 536, p.152119_1 - 152119_8, 2020/08

 Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)

In order to obtain the release rate coefficients from fuels for fast reactors (FRs), heating tests and the subsequent analyses of the fission products (FPs) and actinides that are released were carried out using samples of uranium-plutonium mixed oxide (MOX) fuel pellets irradiated at the experimental fast reactor Joyo. Three heating tests targeting temperatures of 2773, 2973 and 3173 K were conducted using an FP release behavior test apparatus equipped with a high-frequency induction furnace and solid FP sampling systems consisting of a thermal gradient tube (TGT) and filters. Irradiated fuel pellets were placed into a tungsten crucible, then loaded into the induction furnace. The temperature was raised continuously at a heating rate of 10 K/s to the targeted temperature and maintained for 500 s in a flowing argon gas atmosphere. The FPs and actinides released from the MOX fuels and deposited in the TGT and filters were quantified by gamma-ray spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Based on the analysis, the release rates of radionuclides from MOX fuels for FR were obtained and compared with literature data for light water reactor (LWR) fuels. The release rate coefficients of FPs obtained in this study were found to be similar to or lower than the literature values for LWR fuels. It was also found that the release rate coefficient data for actinides were within the range of variation of literature values for LWR fuels.

Journal Articles

Observation of magnon polarization

Nambu, Yusuke*; Barker, J.*; Okino, Yuki*; Kikkawa, Takashi*; Shiomi, Yuki*; Enderle, M.*; Weber, T.*; Winn, B.*; Graves-Brook, M.*; Tranquada, J. M.*; et al.

Physical Review Letters, 125(2), p.027201_1 - 027201_6, 2020/07

 Times Cited Count:24 Percentile:92.46(Physics, Multidisciplinary)

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

Development of the neutron polarizer for the T-violation search using compound nuclei

Okudaira, Takuya; Oku, Takayuki; Sakai, Kenji; Ino, Takashi*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Shinohara, Takenao; Kakurai, Kazuhisa*; Aizawa, Kazuya; Shimizu, Hirohiko*; et al.

Proceedings of Science (Internet), 356, 5 Pages, 2019/12

The technology development section carries out the development of the neutron polarization device: $$^{3}$$He Spin Filter. It is often used for the fundamental physics region. In order to explain the matter-dominated universe, a time reversal violation is necessary and searches for new physics are conducted in the world. The T-violation search using a polarized neutron beam is planned at J-PARC. A large $$^{3}$$He spin filter is needed to polarize high energy neutrons for the experiment and is developed in JAEA. Recently, we developed the accurate measurement system to evaluate the polarization of $$^{3}$$He and a vacuum system to make the $$^{3}$$He spin filter, and large $$^{3}$$He spin filters for epi-thermal neutron was made using the system. The current status of the development of the $$^{3}$$He spin filter will be talked.

Journal Articles

Position-by-position cooling paths within the Toki granite, central Japan; Constraints and the relation with fracture population in a pluton

Yuguchi, Takashi*; Sueoka, Shigeru; Iwano, Hideki*; Izumino, Yuya*; Ishibashi, Masayuki; Danhara, Toru*; Sasao, Eiji; Hirata, Takafumi*; Nishiyama, Tadao*

Journal of Asian Earth Sciences, 169, p.47 - 66, 2019/01

AA2018-0254.pdf:5.48MB

 Times Cited Count:11 Percentile:66.74(Geosciences, Multidisciplinary)

This study presents position-by-position $$t-T$$ paths within a granitic pluton based on thermochronological data, and describes their constraints and their relationship with fracture frequency, as an example from the Toki granite, central Japan. The cooling paths have position-specific characteristics; a single $$t-T$$ path does not represent the cooling behavior of the entire pluton. Such position-specific $$t-T$$ paths enable us to evaluate three-dimensional thermal evolution within the granitic pluton, and thus can clarify the detailed formation history of the entire pluton after the incipient intrusion of the granitic magma into the shallow crust. This study reveals the relationship between position-specific $$t-T$$ paths and fracture frequency, and thus provides a criterion for evaluating the fracture population in terms of thermal stress.

Journal Articles

Safe and rapid development of capillary electrophoresis for ultratrace uranyl ions in radioactive samples by way of fluorescent probe selection for actinide ions from a chemical library

Haraga, Tomoko; Ouchi, Kazuki; Sato, Yoshiyuki; Hoshino, Hitoshi*; Tanana, Rei*; Fujihara, Takashi*; Kurokawa, Hideki*; Shibukawa, Masami*; Ishimori, Kenichiro; Kameo, Yutaka; et al.

Analytica Chimica Acta, 1032, p.188 - 196, 2018/11

 Times Cited Count:10 Percentile:48.63(Chemistry, Analytical)

The development of safe, rapid and highly sensitive analytical methods for radioactive samples, especially actinide (An) ions, represents an important challenge. Here we propose a methodology for selecting appropriate emissive probes for An ions with very low consumption and emission of radioactivity by capillary electrophoresis-laser-induced fluorescence detection (CE-LIF), using a small chemical library of probes with eight different chelating moieties. It was found that the emissive probe, which possesses the tetradentate chelating moiety, was suitable for detecting uranyl ions. The detection limit for the uranyl-probe complex using CE-LIF combined with dynamic ternary complexation and on-capillary concentration techniques was determined to be 0.7 ppt. This method was successfully applied to real radioactive liquid samples collected from nuclear facilities.

Journal Articles

Polarized neutrons

Hiraka, Haruhiro*; Yamaguchi, Yasuo*; Maruyama, Ryuji; Oku, Takayuki; Ino, Takashi*

Hamon, 28(3), p.144 - 149, 2018/08

no abstracts in English

Journal Articles

High oxide-ion conductivity in Si-deficient La$$_{9.565}$$(Si$$_{5.826}$$[]$$_{0.174}$$)O$$_{26}$$ apatite without interstitial oxygens due to the overbonded channel oxygens

Fujii, Kotaro*; Yashima, Masatomo*; Hibino, Keisuke*; Shiraiwa, Masahiro*; Fukuda, Koichiro*; Nakayama, Susumu*; Ishizawa, Nobuo*; Hanashima, Takayasu*; Ohara, Takashi

Journal of Materials Chemistry A, 6(23), p.10835 - 10846, 2018/06

 Times Cited Count:20 Percentile:67.72(Chemistry, Physical)

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:33 Percentile:90.33(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

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

442 (Records 1-20 displayed on this page)