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Journal Articles

High-sensitive XANES analysis at Ce L$$_{2}$$-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samples

Li, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.

Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02

 Times Cited Count:1 Percentile:34.31(Chemistry, Analytical)

no abstracts in English

Journal Articles

Impressions of the 3rd Joint Meeting of Japanese Society of Radiation Safety Management and Japan Health Physics Society

Watanabe, Yuki; Tsuji, Tomoya; Hirota, Seiko*; Hokama, Tomonori; Nakajima, Junya; Tsujiguchi, Takakiyo*; Kimura, Tatsuki*; Koike, Hiromi*; Nakamura, Kaori*; Kuwata, Haruka*; et al.

Hoken Butsuri (Internet), 57(1), p.54 - 64, 2022/03

no abstracts in English

Journal Articles

Impact of PHITS spallation models on the neutronics design of an accelerator-driven system

Iwamoto, Hiroki; Nishihara, Kenji; Iwamoto, Yosuke; Hashimoto, Shintaro; Matsuda, Norihiro; Sato, Tatsuhiko; Harada, Masahide; Maekawa, Fujio

Journal of Nuclear Science and Technology, 53(10), p.1585 - 1594, 2016/10

 Times Cited Count:16 Percentile:85.95(Nuclear Science & Technology)

Journal Articles

SPECT imaging of mice with $$^{99m}$$Tc-radiopharmaceuticals obtained from $$^{99}$$Mo produced by $$^{100}$$Mo(n,2n)$$^{99}$$Mo and fission of $$^{235}$$U

Hashimoto, Kazuyuki; Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi*; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji*; Ota, Masayuki; Konno, Chikara; Ochiai, Kentaro; et al.

Journal of the Physical Society of Japan, 84(4), p.043202_1 - 043202_4, 2015/04

 Times Cited Count:7 Percentile:53.16(Physics, Multidisciplinary)

Journal Articles

Designing a prototype of the ITER pulse scheduling system

Yamamoto, Tsuyoshi; Yonekawa, Izuru*; Ota, Kazuya*; Hosoyama, Hiroki*; Hashimoto, Yasunori*; Wallander, A.*; Winter, A.*; Sugie, Tatsuo; Kusama, Yoshinori; Kawano, Yasunori; et al.

Fusion Engineering and Design, 87(12), p.2016 - 2019, 2012/12

 Times Cited Count:2 Percentile:17.83(Nuclear Science & Technology)

The ITER pulse scheduling system creates, approves and manage parameters that characterize plasma operation of ITER. JAEA analyzed requirements on the ITER plasma operations based on experience operating the JT-60U and designed essential functions. This system was designed to enable the change and reuse of parameters. The functions to support to check consistency between parameters and to assign parameter values are calculated by the system were proposed. These functions are useful to support operators.

Journal Articles

Non-adiabatic transition in C$$_{2}$$H$$_{5}$$OH$$^{+}$$ on a light-dressed potential energy surface by ultrashort pump-and-probe laser pulses

Yazawa, Hiroki*; Shioyama, Tadamasa*; Hashimoto, Hiroshi*; Kannari, Fumihiko*; Itakura, Ryuji; Yamanouchi, Kaoru*

Applied Physics B, 98(2-3), p.275 - 282, 2010/02

 Times Cited Count:5 Percentile:28.75(Optics)

We experimentally investigate the dynamics of vibrational wave packets on the light-dressed-potential energy surface (LD-PES) of C$$_{2}$$H$$_{5}$$OH$$^{+}$$ using a pump-and-probe pulse excitation scheme. The probability of non-adiabatic transition at 800 nm from the singly ionized ground state to the repulsive excited state leading to C-O bond breaking is enhanced when a probe laser pulse is delayed by around 180 fs. At this pulse delay, on the other hand, C-C bond breaking is significantly suppressed. Therefore, the deformation of LDPES is considered to change the direction of the wave packet traveling originally along the C-C stretching into the direction along the C-O stretching. This non-adiabatic transition leading to the redirection of the dissociating wave packet is found to occur more efficiently at the probe laser wavelengths at 400 nm than at 800 nm. The critical pulse delay is still around 180 fs even at 400 nm.

Journal Articles

A Combined method of small-angle neutron scattering and neutron radiography to visualize water in an operating fuel cell over a wide length scale from nano to millimeter

Iwase, Hiroki; Koizumi, Satoshi; Iikura, Hiroshi; Matsubayashi, Masahito; Yamaguchi, Daisuke; Maekawa, Yasunari; Hashimoto, Takeji

Nuclear Instruments and Methods in Physics Research A, 605(1-2), p.95 - 98, 2009/06

 Times Cited Count:31 Percentile:88.62(Instruments & Instrumentation)

We constructed an in-situ and simultaneous observation method as a result of combination between ultra-small-angle neutron scattering and neutron imaging (radiography). With this novel technique, we are able to visualize water distribution or transportation, occurring from micro to macro length scales in a polymer electrolyte fuel cell (PEFC). At a sample position of SANS-J-II at JRR-3, we installed a neutron imaging camera in order to construct an in-situ and simultaneous observation method by USANS and neutron imaging with monochromatized cold neutrons. In addition, in order to selectively observe MEA in a running PEFC by using the in-situ and simultaneous observation method, we need to replace carbon separators which cause strong small-angle scattering as a noise. To reduce this strong background, we replaced the carbon separators with the aluminium ones. As a result, the background scattering was minimized (1/10) as compared to before.

JAEA Reports

Fundamental study on cavitation erosion in liquid metal; Effect of liquid parameter on cavitation erosion in liquid metals (Joint research)

Hattori, Shuji*; Inoue, Fumitaka*; Kurachi, Hiroaki*; Watashi, Katsumi; Tsukimori, Kazuyuki; Hashimoto, Takashi; Yada, Hiroki

JAEA-Research 2008-080, 45 Pages, 2009/02

JAEA-Research-2008-080.pdf:2.86MB

Research on cavitation erosion in liquid metal is very important to confirm the safety of fast breeder reactor using sodium coolant. In this study, a cavitation erosion test apparatus was developed to carry out the erosion tests in low-temperature liquid metals. Cavitation erosion tests were carried out in liquid lead-bismuth alloy and in deionized water. We discuss the effect of liquid parameters and temperature effects on the erosion rate. We reach to the following conclusions. The erosion rate was evaluated in terms of a relative temperature which was defined as the percentage between freezing and boiling points. At 14 $$^{circ}$$C relative temperature, the erosion rate is 10 times in lead-bismuth alloy, and 2 to 5 times in sodium, compared with that in deionized water. The erosion rate can be evaluated as a function of material density and sound velocity. Finally, the temperature dependence was discussed in term of liquid vapor pressure.

Journal Articles

Bacterium organizes hierarchical amorphous structure in microbial cellulose

Koizumi, Satoshi; Zhao, Y.; Tomita, Yoko*; Kondo, Tetsuo*; Iwase, Hiroki; Yamaguchi, Daisuke; Hashimoto, Takeji

European Physical Journal E, 26(1-2), p.137 - 142, 2008/05

 Times Cited Count:53 Percentile:86.07(Chemistry, Physical)

no abstracts in English

Journal Articles

A Focusing-geometry small-angle neutron scattering instrument with a magnetic neutron lens

Oku, Takayuki; Iwase, Hiroki; Shinohara, Takenao; Yamada, Satoru; Hirota, Katsuya*; Koizumi, Satoshi; Suzuki, Junichi; Hashimoto, Takeji; Shimizu, Hirohiko

Journal of Applied Crystallography, 40(s1), p.s408 - s413, 2007/04

 Times Cited Count:26 Percentile:89.69(Chemistry, Multidisciplinary)

Measuring efficiency and/or angular resolution of small-angle neutron scattering experiments can be improved by focusing neutrons on a detector plane. Thus, a magnetic focusing lens (MNL) have been installed into the SANS instrument, SANS-J-II, of JRR-3 in AEA for the focusing-geometry SANS (FSANS) experiments. The MNL is an extended Halbach-type permanent sextupole magnet. The inner diameter and length of the MNL are 35 mm and 1200 mm, respectively. As the MNL functions as the focusing lens only for the polarized neutron with positive polarity, the incident neutron polarization is set positive by using the supermirror polarizer and the two-coil spin flipper. The intensity distribution of the neutrons focused by the MNL at the detector position was measured by using a high-resolution photomultiplier-based scintillation detector. In this paper, the neutron focusing property of the focusing setup is investigated, and the performance of the FSANS instrument is discussed.

Journal Articles

Wide-$$q$$ observation from 10$$^{-4}$$ to 2.0$AA $^{-1}$$ using a focusing and polarized neutron small-angle scattering spectrometer, SANS-J-II

Iwase, Hiroki; Koizumi, Satoshi; Suzuki, Junichi; Oku, Takayuki; Sasao, Hajime*; Tanaka, Hirokazu*; Shimizu, Hirohiko*; Hashimoto, Takeji

Journal of Applied Crystallography, 40(s1), p.s414 - s417, 2007/04

 Times Cited Count:13 Percentile:80.39(Chemistry, Multidisciplinary)

In order to extend an upper q-limit larger, high-angle He sub-detectors were installed on focusing and polarized neutron small-angle scattering spectrometer (SANS-J-II) at JRR-3, Tokai. Consequently, its upper q-limit was improved from 0.2$AA $^{-1}$$ to 2$AA $^{-1}$$. To quantitatively discriminate spin incoherent scattering from hydrogen or to perform nuclear spin polarization contrast variation, a remanent supermirror analyser is also available on the high-angle sub detector. By combining a focusing ultra-small angle scattering, realized by compound and/or magnetic lens and high resolution area detector, SANS-J-II is able to cover from 3$$times$$10$$^{-3}$$ $AA $^{-1}$$ to 2$AA $^{-1}$$ (four order of magnitude of q), which profits to investigate hierarchically ordered system, found widely in hard, soft and bio-materials.

Journal Articles

The Beam diagnostics system for J-PARC synchrotrons

Hayashi, Naoki; Hiroki, Seiji; Sato, Kenichiro; Toyokawa, Ryoji; Arakawa, Dai*; Lee, S.*; Hashimoto, Yoshinori*; Miura, Takako*; Toyama, Takeshi*

KEK Proceedings 2006-15 (CD-ROM), p.128 - 130, 2007/03

The beam diagnostics system for J-PARC synchrotrons (RCS and MR) will be presented. The design of the system will be described for high current machines. Some test results will be reported.

Journal Articles

Effects of annealing temperatures on some radiation-induced phenomena in natural quartz

Fujita, Hiroki; Hashimoto, Tetsuo*

Radiation Measurements, 42(2), p.156 - 162, 2007/02

 Times Cited Count:5 Percentile:37.26(Nuclear Science & Technology)

Red thermoluminescence (RTL), electron spin resonance (ESR) centers and kinetic parameter for RTL electron trap were investigated in combination with annealing experiments. The ESR for Ti-centers was measured in conjunction with Al-centers at 77 K upon warming up to room temperature. Only three kinds of Ti-centers were experimentally observed as the electron-trapped center in the ESR measurement. The [TiO$$_{4}$$/ H$$^{+}$$]$$^{0}$$, the [TiO$$_{4}$$/ Li$$^{+}$$]$$^{0}$$and the [TiO$$_{4}$$/ Na$$^{+}$$]$$^{0}$$centers were affected by annealing treatment. The [TiO$$_{4}$$/ H$$^{+}$$]$$^{0}$$centers behaved just like radical H$$^{0}$$atoms derived from radiolysis of H-related impurities. Tendency of [TiO$$_{4}$$/ Na$$^{+}$$]$$^{0}$$centers was resemble to the changes of RTL-intensities associated with annealing temperatures. The phenomena were supported by both the results of RTL measurement as well as kinetic parameters, which were determined by RTL measurement were also influenced by the annealing temperatures and were found to be correlated with broadening of RTL peak after annealing treatments.

Journal Articles

Usability of VTL from natural quartz grains for retrospective dosimetry

Fujita, Hiroki; Hashimoto, Tetsuo*

Radiation Protection Dosimetry, 123(2), p.143 - 147, 2007/02

 Times Cited Count:6 Percentile:42.6(Environmental Sciences)

To develop retrospective dosimetry of unexpected radiation accident, the basic studies on violet thermoluminescence (VTL) phenomena were conducted using natural quartz grains. All VTL glowcurves of as-received samples exhibited no peaks below 250 $$^{circ}$$C, although there remained VTL peaks in the temperature region below 250 $$^{circ}$$C for artificially irradiated quartz samples. Therefore, accident doses could be estimated without interference of naturally accumulated doses by VTL measurement from natural quartz. The mean lives of VTL were evaluated by the various heating rates method and then the range of values was between some days and ten thousands of years depending on each peak. Especially, the mean life of VTL peak at 200 $$^{circ}$$C was years order. Furthermore, the lower detection limit was calculated to be tens of mGy from the response curve. This value was lower than that of other methods such as ESR dosimetry. From these results, VTL dosimetry would be preferable for accidental evaluation.

Journal Articles

Focusing and Polarized Neutron ultra-small-angle scattering spectrometer (SANS-J-II) at research reactor JRR3, Japan

Koizumi, Satoshi; Iwase, Hiroki; Suzuki, Junichi; Oku, Takayuki; Motokawa, Ryuhei; Sasao, Hajime*; Tanaka, Hirokazu; Yamaguchi, Daisuke; Shimizu, Hirohiko; Hashimoto, Takeji

Physica B; Condensed Matter, 385-386(2), p.1000 - 1006, 2006/11

 Times Cited Count:39 Percentile:80.73(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Influence of radioluminescence on optically stimulated luminescence from natural quartz grains

Fujita, Hiroki; Hashimoto, Tetsuo*

Radioisotopes, 55(3), p.117 - 123, 2006/03

The causes of the different optically stimulated luminescence (OSL) sensitivities for quartz aliquots from different origins were investigated concerning influence of radioluminescence (RL) during artificial irradiation. All RL spectra from red-thermoluminescence (RTL) quartz grains consist of two broad RL emission peaks, assignable to a violet region (V-RL) of a 400 nm peak and a red one (R-RL) of a 630 nm one from an on-line RL-spectrometric analysis. The OSL sensitivities were affected on the total amounts of V-RL intensities during irradiation of a fixed total dose (20 Gy) with different dose rates. Additionally, the bleaching effects of RL with shorter wavelength than blue-region were assured from another experiment with the combination of quartz slices and optical filter. Conclusively, it is suggested that the V-RL emissions appreciably affect the residual or naturally accumulated doses when OSL/SAR protocol was applied.

Journal Articles

Self-Bleaching Effects of Radioluminescence on OSL-Responses of Natural Quartz Samples

Fujita, Hiroki; Hashimoto, Tetsuo*

11th International Conference on Luminescence and Electron Spin Resonance Dating (LED 2005), Book of Abstracts, p.68, P. 68, 2005/07

Radioluminescence (RL) phenomena can be observed from many insulating minerals including quartz during radiation-irradiation. The RL attracts much attention to the purpose of both the alternative dosimetry and the elucidation of luminescence mechanism.RL spectrum consists of two RL emission regions assigned to emission peaks at 400 (violet region) and 630nm (Red region) on natural quartz by using an on-line spectrometric system. Increment of RL intensities was observed by increasing dose rate. When the sample was irradiated beforehand, the RL emission intensities depended on the predoses. The above phenomena will lead to a possibility to determine doses using RL measurement. The RL emission peak at 400nm was almost close to stimulated wavelength (470nm) on optically stimulated luminescence (OSL)-measurements. Therefore OSL source would be stimulated by the RL emission wavelength. Overestimated or underestimated OSL-doses were occurred by measuring conditions (high- and low-dose rate), and quartz origins, compared with applied dose. The OSL-doses was related to violet-RL (V-RL) emission intensity but red-RL (R-RL). This result suggested that OSL source would be stimulated by V-RL emission within quartz grain. However, estimated doses by red-TL (RTL) and blue-TL (BTL) measurements were less or not affected by dose rate. These results imply that RL emission is more effective to OSL measurement than TL measurement.

Journal Articles

Scenario to focusing polarized small-angle neutron scattering spectrometer SANS-J-II

Koizumi, Satoshi; Iwase, Hiroki; Tanaka, Hirokazu; Hashimoto, Takeji; Suzuki, Junichi; Oku, Takayuki; Sasao, Hajime*; Shimizu, Hirohiko

Hamon, 14(4), p.266 - 274, 2004/10

no abstracts in English

Oral presentation

Microstructures of poly (N-isopropylacrylamide) in water studied by focusing Ultra-Small Angle Neutron Scattering (SANS-J-II)

Koizumi, Satoshi; Motokawa, Ryuhei; Iwase, Hiroki; Hashimoto, Takeji

no journal, , 

no abstracts in English

Oral presentation

Small-angle neutron scattering study of aggregation properties of heterogemini surfactants containing sugar moiety

Iwase, Hiroki; Koizumi, Satoshi; Yoshimura, Tomokazu*; Hashimoto, Takeji

no journal, , 

no abstracts in English

55 (Records 1-20 displayed on this page)