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A Cubic CeBr$$_{3}$$ gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power Station

冠城 雅晃; 島添 健次*; 大鷹 豊*; 上ノ町 水紀*; 鎌田 圭*; Kim, K. J.*; 吉野 将生*; 庄子 育宏*; 吉川 彰*; 高橋 浩之*; et al.

Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08

 被引用回数:0 パーセンタイル:100(Instruments & Instrumentation)

Our work focused on the passive gamma-ray analysis (PGA) of the nuclear fuel debris based on measuring gamma rays with an energy greater than 1 MeV for the decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). The PGA requires gamma-ray spectrometers to be used under the high dose rates in the FDNPS, then we fabricated a small cubic CeBr$$_{3}$$ spectrometer with dimensions of 5 mm $$times$$ 5 mm $$times$$ 5 mm, coupled to a Hamamatsu R7600U-200 photomultiplier tube (PMT). The performance at dose rates of 4.4 to 750 mSv/h in a $$^{60}$$Co field was investigated. The energy resolution (FWHM) at 1333 keV ranged from 3.79% to 4.01%, with a standard deviation of 6.9%, which met the narrow gamma decay spectral lines between $$^{154}$$Eu (1274 keV) and $$^{60}$$Co (1333 keV). However, the spectra shifted to a higher energy level as the dose rate increase, there was a 51% increase at the dose rates of 4.4 to 750 mSv/h, which was caused by the PMT gain increase.


Giant spin hydrodynamic generation in laminar flow

高橋 遼*; 中堂 博之; 松尾 衛; 針井 一哉*; 大沼 悠一*; 前川 禎通; 齊藤 英治

Nature Communications (Internet), 11, p.3009_1 - 3009_6, 2020/06

 被引用回数:0 パーセンタイル:100(Multidisciplinary Sciences)

Hydrodynamic motion can generate a flux of electron-spin's angular momentum via the coupling between fluid rotation and electron spins. Such hydrodynamic generation, called spin hydrodynamic generation (SHDG), has recently attracted attention in a wide range of fields, especially in spintronics. Spintronics deals with spin-mediated interconversion taking place on a micro or nano scale because of the spin-diffusion length scale. To be fully incorporated into the interconversion, SHDG physics should also be established in such a minute scale, where most fluids exhibit a laminar flow. Here, we report electric voltage generation due to the SHDG in a laminar flow of a liquid-metal mercury. The experimental results show a scaling rule unique to the laminar-flow SHDG. Furthermore, its energy con- version efficiency turns out to be about 105 greater than of the turbulent one. Our findings reveal that the laminar-flow SHDG is suitable to downsizing and to extend the coverage of fluid spintronics.


Pre- and post-accident $$^{14}$$C activities in tree rings near the Fukushima Dai-ichi Nuclear Power Plant

松中 哲也*; 笹 公和*; 高橋 努*; 松村 万寿美*; 佐藤 志彦; Shen, H.*; 末木 啓介*; 松崎 浩之*

Radiocarbon, 61(6), p.1633 - 1642, 2019/12

 被引用回数:0 パーセンタイル:100(Geochemistry & Geophysics)

Areas affected by routine radiocarbon ($$^{14}$$C) discharges from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) and accidental releases in March 2011 were investigated by analysis of cores from Japanese cypress and cedar trees growing at sites 9 and 24 km northwest of the plant. $$^{14}$$C concentrations in tree rings from 2008-2014 (before and after the accident) were determined by accelerator mass spectrometry, with $$^{14}$$C activities in the range 231-256 Bq kg$$^{-1}$$ C. Activities during the period 2012-2014, after FDNPP shutdown, represent background levels, while the significantly higher levels recorded during 2008-2010, before the accident, indicate uptake of $$^{14}$$C from routine FDNPP operations. The mean excess $$^{14}$$C activity for the pre-accident period at the sites 9 and 24 km northwest of the plant were 21 and 12 Bq kg$$^{-1}$$ C, respectively, indicating that the area of influence during routine FDNPP operations extended at least 24 km northwest. The mean excess tree-ring $$^{14}$$C activities in 2011 were 10 and 5.8 Bq kg$$^{-1}$$ C at 9 and 24 km northwest, respectively, documenting possible impact of the FDNPP accident on $$^{14}$$C levels in trees.


Analysis of the high-dose-range radioresistance of prostate cancer cells, including cancer stem cells, based on a stochastic model

嵯峨 涼*; 松谷 悠佑; 高橋 玲*; 長谷川 和輝*; 伊達 広行*; 細川 洋一郎*

Journal of Radiation Research, 60(3), p.298 - 307, 2019/05

 被引用回数:7 パーセンタイル:9.54(Biology)



Development of compact high field pulsed magnet system for new sample environment equipment at MLF in J-PARC

渡辺 真朗; 野尻 浩之*; 伊藤 晋一*; 河村 聖子; 木原 工*; 益田 隆嗣*; 佐原 拓郎*; 左右田 稔*; 高橋 竜太

JPS Conference Proceedings (Internet), 25, p.011024_1 - 011024_5, 2019/03

近年、中性子や放射光をプローブとした数10T以上の強磁場下で行う実験・研究への要望が増えてきている。強磁場装置を用いた中性子散乱実験は、例えば、磁場誘起超伝導体などにおける強磁場中磁気相関の研究やマルチフェロイック物質などの新しい凝縮系の研究などが挙げられる。J-PARC MLFでは、強磁場パルスマグネットシステムの開発をおこなった。一般的に数10テスラ以上の強磁場装置は大規模になるが、開発する装置はMLFの既存のビームラインに対して設置可能な小型な装置でなければならない。そこで数ミリ秒程度磁場を発生させるパルスマグネットシステムを開発した。パルス磁場にすることで、強磁場を達成しつつエネルギー・パワーを抑えることで装置の小型化が可能である。30テスラを発生可能なパルスマグネットシステムを実現するためには、高電圧・大電流パルス電源および、強磁場に耐えられるコイルと試料スティックが必要である。本発表では、開発したパルスマグネットシステムの詳細およびMLFビームライン(HRC)にて行なった中性子ビーム利用実験でのパルスマグネットシステムの状況について報告する。


Gamma-ray imaging system for Fukushima Daiichi Nuclear Power Plant using silicon strip detector

冠城 雅晃; 佐藤 優樹; 吉原 有里*; 島添 健次*; 高橋 浩之*; 鳥居 建男

Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.405 - 414, 2018/11

 被引用回数:0 パーセンタイル:100

On March 11, 2011, a massive earthquake occurred in the Tohoku region of Japan, and a large tsunami hit the Fukushima Daiichi Nuclear Power Plant (1F), resulting in a nuclear accident. Despite the years that have passed since the accident, decommissioning remains a concern. Radiation measurement techniques are very important for accelerating the decommissioning and ensuring low radiation exposure to workers. Our gamma-ray imaging system is the detection device for determining the three dimensional radioactive distributions of nuclear fuel debris, measuring high-energy gamma rays (greater than 1 MeV). Silicon semiconductor detectors are among the candidate detectors for radiation measurements in our system because of their radiation-hardness and high counting rate capability. We have been developing a stacked amorphous-silicon (Si)/crystal-Si heterojunction Si strip detector, which has 1-mm-pitch striped electrodes (0.5 mm wide) and 1.2-mm-pitch stacked technology. The detector consists of an Si strip mounted on a thin printed circuit board, front-end readout electronics with a complementary metal oxide semiconductor application specific integrated circuit, and a field programmable gate array. The threshold level of energy deposition of each pulse signal in each channel can be set from the application-specific integrated circuit, and gamma-ray images with energy discrimination can be obtained. The energy threshold level for discrimination of $$^{60}$$Co gamma rays from $$^{137}$$Cs gamma rays was investigated experimentally and by means of simulation, and it was found to be about 500 keV. Therefore, our Si strip detector has the required position sensitivity and energy discrimination ability for identifying high-energy gamma-ray source distributions.


Fabrication and magnetic control of Y$$_3$$Fe$$_5$$O$$_{12}$$ cantilevers

Seo, Y.-J.*; 針井 一哉; 高橋 遼*; 中堂 博之; 大柳 洸一*; Qiu, Z.*; 小野 崇人*; 塩見 雄毅*; 齊藤 英治

Applied Physics Letters, 110(13), p.132409_1 - 132409_4, 2017/03

 被引用回数:11 パーセンタイル:29.06(Physics, Applied)



Field test around Fukushima Daiichi Nuclear Power Plant site using improved Ce:Gd$$_{3}$$(Al,Ga)$$_{5}$$O$$_{12}$$ scintillator Compton camera mounted on an unmanned helicopter

志風 義明; 西澤 幸康; 眞田 幸尚; 鳥居 建男; Jiang, J.*; 島添 健次*; 高橋 浩之*; 吉野 将生*; 伊藤 繁樹*; 遠藤 貴範*; et al.

Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12

 被引用回数:18 パーセンタイル:4.57(Nuclear Science & Technology)



Age and speciation of iodine in groundwater and mudstones of the Horonobe area, Hokkaido, Japan; Implications for the origin and migration of iodine during basin evolution

東郷 洋子*; 高橋 嘉夫*; 天野 由記; 松崎 浩之*; 鈴木 庸平*; 寺田 靖子*; 村松 康行*; 伊藤 一誠*; 岩月 輝希

Geochimica et Cosmochimica Acta, 191, p.165 - 186, 2016/10

 被引用回数:13 パーセンタイル:32.21(Geochemistry & Geophysics)



SENJU; A New time-of-flight single-crystal neutron diffractometer at J-PARC

大原 高志; 鬼柳 亮嗣; 及川 健一; 金子 耕士; 川崎 卓郎; 田村 格良; 中尾 朗子*; 花島 隆泰*; 宗像 孝司*; 茂吉 武人*; et al.

Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02

 被引用回数:24 パーセンタイル:6.08(Chemistry, Multidisciplinary)

SENJU, a time-of-flight Laue-type single-crystal neutron diffractometer, was developed at the Materials and Life Science Experimental Facility (MLF) of the Japan Accelerator Research Complex (J-PARC). Molecular structure analysis of a sub-millimeter taurine crystal and magnetic structure analysis of a MnF$$_{2}$$ crystal were performed to evaluate its performance.


Spin hydrodynamic generation

高橋 遼*; 松尾 衛; 小野 正雄; 針井 一哉; 中堂 博之; 岡安 悟; 家田 淳一; 高橋 三郎*; 前川 禎通; 齊藤 英治

Nature Physics, 12, p.52 - 56, 2016/01

 被引用回数:41 パーセンタイル:6.49(Physics, Multidisciplinary)

Magnetohydrodynamic generation is the conversion of fluid kinetic energy into electricity. Such conversion, which has been applied to various types of electric power generation, is driven by the Lorentz force acting on charged particles and thus a magnetic field is necessary. On the other hand, recent studies of spintronics have revealed the similarity between the function of a magnetic field and that of spin-orbit interactions in condensed matter. This suggests the existence of an undiscovered route to realize the conversion of fluid dynamics into electricity without using magnetic fields. Here we show electric voltage generation from fluid dynamics free from magnetic fields; we excited liquid-metal flows in a narrow channel and observed longitudinal voltage generation in the liquid. This voltage has nothing to do with electrification or thermoelectric effects, but turned out to follow a universal scaling rule based on a spin-mediated scenario. The result shows that the observed voltage is caused by spin-current generation from a fluid motion: spin hydrodynamic generation. The observed phenomenon allows us to make mechanical spin-current and electric generators, opening a door to fluid spintronics.


Barnett effect in paramagnetic states

小野 正雄; 中堂 博之; 針井 一哉; 岡安 悟; 松尾 衛; 家田 淳一; 高橋 遼*; 前川 禎通; 齊藤 英治

Physical Review B, 92(17), p.174424_1 - 174424_4, 2015/11

 被引用回数:14 パーセンタイル:36.69(Materials Science, Multidisciplinary)

We report the observation of the Barnett effect in paramagnetic states by mechanically rotating gadolinium (Gd) metal with a rotational frequency of up to 1.5 kHz above the Curie temperature. An in situ magnetic measurement setup comprising a high-speed rotational system and a fluxgate magnetic sensor was developed for the measurement. Temperature dependence of the observed magnetization follows that of paramagnetic susceptibility, indicating that any emergent magnetic field is proportional to the rotational frequency and is independent of temperature. From the proportionality constant of the emergent field, the gyromagnetic ratio of Gd is calculated to be -29 $$pm$$ 5 GHz/T. This study revisits the primordial issue of magnetism with modern technologies to shed new light on the fundamental spin-rotation coupling.


J-PARC E19 experiment; Pentaquark $$Theta^+$$ search in hadronic reaction at J-PARC

高橋 智則*; 江川 弘行; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.

JPS Conference Proceedings (Internet), 8, p.022011_1 - 022011_6, 2015/09

A search for the $$Theta^+$$ pentaquark in the $$pi^-p to K^-X$$ reaction was performed at the J-PARC Hadron Facility. Two data samples were collected in 2010 and 2012 at $$pi^-$$ beam momenta of 1.92 and 2.0 GeV/$$c$$, respectively. No peak structure was observed in the missing mass spectra obtained from either data set. The upper limit for the production cross section averaged over the scattering-angle range of $$2^{circ}$$ to $$15^{circ}$$ in the laboratory frame was found to be 0.28 $$mu$$b/sr. The decay width of the $$Theta^+$$ can be directly connected to the production cross section through a theoretical calculation using an effective Lagrangian. The estimated upper limits of the width were 0.41 and 2.8 MeV for the spin-parities of $$1/2^+$$ and $$1/2^-$$, respectively.


Cosmic-ray test of a time-of-flight detector for double-strangeness experiments at J-PARC

Kim, S. H.*; Hwang, S.; Ahn, J. K.*; 江川 弘行; 早川 修平; Hong, B.*; 細見 健二; 今井 憲一; Kim, M. H.*; Lee, J. Y.*; et al.

Nuclear Instruments and Methods in Physics Research A, 795, p.39 - 44, 2015/09

 被引用回数:3 パーセンタイル:62.51(Instruments & Instrumentation)

We have developed a time-of-flight (ToF) array consisting of 24 plastic scintillators for triggering and timing measurements in a series of planned experiments to study double-strangeness hadronic and nuclear systems at the K1.8 beamline of J-PARC. Each ToF scintillator is 180 cm long with a cross-section of 8$$times$$3 cm$$^{2}$$ and is read out by H1949-50 photomultiplier tubes at both ends. The timing and attenuation properties of the scintillators are measured using cosmic-ray muons and $$beta$$ rays from $$^{90} {rm Sr}$$. The cosmic-ray muon events are triggered by three pairs of 120-cm-long plastic scintillators, sandwiching the ToF array. The intrinsic time resolutions of the scintillators are estimated to be in the range 60-100 ps, which is adequate for reliable separation between $$pi$$ and $$K$$ at 1.2 GeV/$$c$$. The attenuation length is measured to be approximately 210 cm, which is half that for a bulk scintillator.


Precise determination of $$^{12}_{Lambda}$$C level structure by $$gamma$$-ray spectroscopy

細見 健二; Ma, Y.*; 味村 周平*; 青木 香苗*; 大樂 誠司*; Fu, Y.*; 藤岡 宏之*; 二ツ川 健太*; 井元 済*; 垣口 豊*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08

 被引用回数:12 パーセンタイル:29.71(Physics, Multidisciplinary)

$$gamma$$線分光によって$$^{12}_{Lambda}$$Cハイパー核のレベル構造を精密に測定した。ゲルマニウム検出器群Hyperball2を用いて、$$^{12}$$C$$(pi^{+}, K^{+}gamma)$$反応からの4本の$$gamma$$線遷移を同定することに成功した。基底状態スピン二重項$$(2^{-}, 1^{-}_{1})$$のエネルギー間隔は直接遷移$$M1$$$$gamma$$線により、$$161.5pm0.3$$(stat)$$pm0.3$$(syst)keVと測定された。また、励起準位である$$1^{-}_{2}$$$$1^{-}_{3}$$について、それぞれ、$$2832pm3pm4$$, keVと$$6050pm8pm7$$, keVと励起エネルギーを決定した。これらの測定された$$^{12}_{Lambda}$$Cの励起エネルギーは反応分光による$$lambda$$ハイパー核の実験研究において決定的な基準となる。



小泉 安郎; 高橋 和希*; 上澤 伸一郎; 吉田 啓之; 高瀬 和之

第52回日本伝熱シンポジウム講演論文集(CD-ROM), P. 2, 2015/06



Study on heat transfer surface temperature variation during pool nucleate boiling by measuring instantaneous surface temperature distribution with infrared radiation camera

小泉 安郎; 高橋 和希*; 上澤 伸一郎; 吉田 啓之; 高瀬 和之

Proceedings of 9th International Conference on Boiling and Condensation Heat Transfer (Boiling & Condensation 2015) (DVD-ROM), 10 Pages, 2015/04



Recovery of scandium from hot spring water with graft adsorbent containing phosphoric groups

保科 宏行; 笠井 昇; 天田 春代; 高橋 牧克*; 田中 和也*; 瀬古 典明

日本イオン交換学会誌, 25(4), p.248 - 251, 2014/11

An adsorbent for Scandium (Sc) recovery was developed with radiation-induced graft polymerization of phosphoric acids that have a high affinity for Sc onto polyethylene fabrics. The adsorption performance of Sc was evaluated with the Sc adsorption equipment, consisting of 155 mm internal diameter columns and a pump that were set up near Yukawa River in Kusatsu town. To achieve a practical use of Sc recovery, the adsorbent requires repeated use with maintaining its efficiency in terms of cost reduction. So, the reusability of the adsorbent was investigated by repeating adsorption and elution. The breakthrough curves of Sc adsorption showed similar behavior in all tests. The adsorbed Sc from the 19th adsorption test was 56 mg, which was comparable capacity to the average amount of the adsorbed Sc during the 19 tests. These results indicated that the adsorbent was used more than 19 times with maintaining high adsorption performance of Sc.


A New eco-friendly synthesis method for arsenic adsorbent

天田 春代; 高橋 牧克*; 保科 宏行; 瀬古 典明

日本イオン交換学会誌, 25(4), p.109 - 113, 2014/11

A large amount of arsenic waste solution which was dissolved in neutral aqueous media, was generated from the manufacturing process of gallium arsenide component in semiconductor industry. As for arsenic removal, an adsorbent was developed by radiation graft polymerization and subsequent chemical modification with N-methyl-D-glucamine (NMDG) as a functional group. Furthermore, the grafting and the modification were carried out using water based solvent instead of organic solvent in view of an environmental emission and a working environment. The solvents were comprised of water and surfactant, and the adsorption performances compared with a conventional method synthesized in 1,4-dioxane of organic solvent. Total amount of arsenic for arsenic(III) and arsenic(V) at pH 6.5 were 3.2 times and 2.1 times higher than our previous fibrous adsorbent. From the pH dependency studies, the developed grafted adsorbent gave high removal ratio in a neutral media area for both arsenic species. Breakthrough capacities in the column mode tests for arsenic(III) and arsenic(V) were 0.3 and 18 mg/g at pH 6.5, respectively.


Present state of TEM-SXES analysis and its application to SEM aiming chemical analysis of bulk materials

寺内 正己*; 高橋 秀之*; 飯田 信雄*; 村野 孝訓*; 小池 雅人; 今園 孝志; 小枝 勝*; 長野 哲也*; 笹井 浩行*; 大上 裕紀*; et al.

Microscopy and Microanalysis, 20(Suppl.3), p.682 - 683, 2014/08

電子顕微鏡(TEM及びEPMA)に取り付け可能な軟X線発光分光器(SXES)を開発した。これは4枚の不等間隔溝回折格子を備え、50$$sim$$4000eVのエネルギー範囲を測定できる。これとTEMを組み合わせたTEM-SXES装置は、電子エネルギー損失分光器やエネルギー分散型分光器では計測困難な局所領域の価電子帯に関する情報を取得できる。SXES装置を材料開発・評価の現場へ広く普及させる観点から、試料の薄膜化を必要としないSEMにも搭載できるようにした。SEMはTEMに比して空間分解能で劣るもののプローブ電流量が大きい上、幅広い物質、特に、バルク物質を扱えるため汎用性が高い。本研究では、Al金属間化合物(Al$$_2$$Au, Al$$_2$$Co)のバルク試料からのAl-L発光測定において結晶構造の違いAl(FCC), Al$$_2$$Au(CaF$$_2$$), Al$$_2$$Co(CsCl)に起因するバンド構造の差異が反映されたスペクトルを得ることができた。このように、SEMによるSXES測定は、バルク試料に対して状態密度の顕微マッピング分析が可能な技術として有用であると考えられる。

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