U-Pb dating of calcite using LA-ICP-MS; Instrumental setup for non-matrix-matched age dating and determination of analytical areas using elemental imaging

Yokoyama, Tatsunori; Kimura, Junichi*; Mitsuguchi, Takehiro; Danhara, Toru*; Hirata, Takafumi*; Sakata, Shuhei*; Iwano, Hideki*; Maruyama, Seiji*; Chang, Q.*; Miyazaki, Takashi*; et al.

Geochemical Journal, 52(6), p.531 - 540, 2018/12

https://doi.org/10.2343/geochemj.2.0541

Local structures and magnetic properties of fullerene-Co systems studied by XAFS and XMCD analyses

Hojo, Ikuko*; Koide, Akihiro*; Matsumoto, Yoshihiro; Maruyama, Takashi*; Nagamatsu, Shinichi*; Entani, Shiro; Sakai, Seiji; Fujikawa, Takashi*

Journal of Electron Spectroscopy and Related Phenomena, 185(1-2), p.32 - 38, 2012/03

https://doi.org/10.1016/j.elspec.2011.11.001

Demonstration of magnetic field imaging in a permalloy film with neutron spin phase contrast imaging

Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Tasaki, Seiji*; Hino, Masahiro*; Matsubayashi, Masahito

Nuclear Instruments and Methods in Physics Research A, 634(1, Suppl.), p.S90 - S93, 2011/04

https://doi.org/10.1016/j.nima.2010.06.363

In a neutron spin interferometer (NSI), incident neutrons are in states of up- and down-spin eigenstates and a phase difference between the eigenstates is observed after transmission through a magnetic sample. Since the phase difference is proportional to an integral of magnetic field along a trajectory of neutrons, NSI imaging provides projection images of a distribution of magnetic field in the sample. We tried to visualize magnetic field in permalloy film with and without stress as a demonstration of the NSI imaging. An experiment was carried out at C3-1-2-2, MINE2 port at the neutron guide hall of JRR-3M with wavelength of 0.88nm and wavelength resolution of 0.3% in FWHM. Permalloy film with thickness of 0.1 mm was used as a sample and was stressed by bending with angles of 45 and 180 . As a result, images of decrease of a saturated magnetization and an increase of leak magnetic field with increasing the bending angle were obtained.

Evaluation of containment failure probability by Ex-vessel steam explosion in Japanese LWR plants

Moriyama, Kiyofumi; Takagi, Seiji*; Muramatsu, Ken; Nakamura, Hideo; Maruyama, Yu*

Journal of Nuclear Science and Technology, 43(7), p.774 - 784, 2006/07

https://doi.org/10.3327/jnst.43.774

The containment failure probability due to ex-vessel steam explosions was evaluated for Japanese BWR and PWR model plants. A stratified Monte Carlo technique (Latin Hypercube Sampling (LHS)) was applied for the evaluation of steam explosion loads, in which a steam explosion simulation code JASMINE was used as a physics model. The evaluation was made for three scenarios: a steam explosion in the pedestal area or in the suppression pool of a BWR model plant with a Mark-II containment, and in the reactor cavity of a PWR model plant. The scenario connecting the generation of steam explosion loads and the containment failure was assumed to be displacement of the reactor vessel and pipings, and failure at the penetration in the containment boundary. The mean conditional containment failure probabilities (CCFPs) were (mean) and (median) for the BWR suppression pool case, (mean) and (median) for the BWR pedestal case, and (mean) and (median) for the PWR cavity case. Note that the specific values of the probability are most dependent on assumed range of melt flow rates and on fragility curves that involve conservatism and uncertainty due to simplified scenarios and limited information. Also, note that these CCFPs were based on the preconditions of failure of accident termination within the reactor vessel, relocation of the core melt into the water pool at the place in question without significant interference, and a strong triggering ofa steam explosion with maximized premixed mass for the given premixing condition. The evaluation of CCFPs on the basis of core damage needs consideration of probabilities for these preconditions. Thus, the CCFPs per core damage should be lower than the values given above.

Chopper mode of Drabkin energy filters for pulsed neutron sources

Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Takeda, Masayasu; Maruyama, Ryuji*; Tasaki, Seiji*

Physica B; Condensed Matter, 356(1-4), p.174 - 177, 2005/02

https://doi.org/10.1016/j.physb.2004.10.071

Drabkin energy filter could be used as a fast chopper for pulsed neutrons by varying the resonant wavelength fast in such a way that resonant wavelength matches neutron wavelength at a small time region. The faster are varied, the smaller time window we could obtain. Neutron pulses could be sharpened much more effectively for a small wavelength band than in the wide-band pulse-shaping mode in which is varied in synchronization with the time-of-flight from the moderator. In our preliminary test of a chopper-mode with a prototype Drabkin energy filter, time-window of 0.21 ms was obtained while it was 1.08 ms with the filter driven stationary. Narrower time-window could have been obtained if we had more beam-time and it could be also narrowed with higher-resolution Drabkin filters.

Development of a spin flipper for an application of a neutron magnetic device

Oku, Takayuki*; Sakai, Kenji*; Adachi, Tomohiro*; Ikeda, Kazuaki*; Shimizu, Hirohiko*; Maruyama, Ryuji*; Hino, Masahiro*; Tasaki, Seiji*; Kiyanagi, Yoshiaki*; Kamiyama, Takashi*; et al.

Physica B; Condensed Matter, 335(1-4), p.226 - 229, 2003/07

https://doi.org/10.1016/S0921-4526(03)00243-6

no abstracts in English

Visualization of current density distributions with neutron spin interferometer

Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Takenaka, Nobuyuki*; Kageyama, Masashi*; Tasaki, Seiji*; Hino, Masahiro*; Kawabata, Yuji*; et al.

no journal, , 

no abstracts in English

Visualization of magnetic field with Neutron Spin Interferometer

Hayashida, Hirotoshi; Yamazaki, Dai; Ebisawa, Toru*; Maruyama, Ryuji; Soyama, Kazuhiko; Iikura, Hiroshi; Yasuda, Ryo; Sakai, Takuro; Matsubayashi, Masahito; Takenaka, Nobuyuki*; et al.

no journal, , 

no abstracts in English

A Survey on new standard materials for U-Pb dating of carbonate using LA-ICP-MS

Yokoyama, Tatsunori; Kokubu, Yoko; Murakami, Hiroaki; Watanabe, Takahiro; Hirata, Takafumi*; Sakata, Shuhei*; Danhara, Toru*; Iwano, Hideki*; Maruyama, Seiji*; Miyazaki, Takashi*; et al.

no journal, , 

Chronological and geochemical studies of carbonates, which are commonly found as fracture filling minerals in rocks, can provide information about geochemical conditions present during formation including in deep subsurface environments. A dating technique for the carbonates using laser ablation-multiple collector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) is still immature partly because of a lack of a consensus international carbonate standard for the in-situ dating technique. In this study, we performed a survey on the carbonate standard materials that may be suitable for high precision U-Th-Pb dating using LA-MC-ICPMS. We examined carbonate standard materials JCp-1 and JCt-1 issued by the Geological Survey of Japan (GSJ). Based on solution-based bulk analysis using MC-ICP-MS, heterogeneities in Pb isotope compositions were confirmed. Nevertheless, the 206Pb-based isotopic compositions were all within 1.2 per mill variations acceptable for a standard used for age determination using LA-MC-ICPMS. Additional tests on the heterogenities in U-Th-Pb compositions of the carbonate standards along with determinations of other trace elements using a 2D imaging LA-ICP-MS are ongoing. Examinations on both natural standards and synthetic standards are ongoing for further efforts in determination of the standard suitable for U-Th-Pb dating of carbonates.

U-Pb dating of calcium carbonate using LA-MC-ICPMS

Yokoyama, Tatsunori; Kokubu, Yoko; Mitsuguchi, Takehiro; Murakami, Hiroaki; Hirata, Takafumi*; Sakata, Shuhei*; Danhara, Toru*; Iwano, Hideki*; Maruyama, Seiji*; Miyazaki, Takashi*; et al.

no journal, , 

Chronological and geochemical studies of calcium carbonates can provide precious information for changes in geochemical condition in deep geological environments. Because the carbonate can be found as common filling minerals in rocks, age zoning and spatial distribution of chemical composition in the carbonate could be a wide-use indicator to reconstruct the past environmental changes. Calcite and other carbonate materials have been dated by Isotope Dilution-Thermal Ionization Mass Spectrometry. On the other hand, a few of U-Pb dating studies in a micro scale area (less than 10 micrometer) such as using laser ablation-multiple collector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) has been conducted on the carbonate. The U-Pb dating technique for the carbonates using LA-MC-ICPMS is still immature partly because of a lack of consensus international carbonate reference materials for the in-situ dating technique. In order to solve this problem, we performed a survey on the carbonate reference materials that may be suitable for high precision U-Pb dating using LA-MC-ICPMS. Additionally, we conducted experiments to make compositionally homogeneous carbonate (calcite) reference materials.