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J-PARC MRのFXセプタムとFXキッカーのインピーダンスの評価と対策

小林 愛音*; 外山 毅*; 中村 剛*; 菖蒲田 義博; 石井 恒次*

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (インターネット), p.287 - 291, 2021/10

加速器を構成する要素のビーム結合インピーダンスの影響の見積もりと対策は、それにより引き起こされるビームの集団効果を抑制し、ビーム強度を上げるために不可欠である。J-PARC main ring (MR)は現在の最高強度515kW ($$2.8 times 10^{14}$$ ppp, MR cycle 2.48 sec)から750kW ($$2.03 times 10^{14}$$ ppp, 1.3sec)、さらには1.3MW ($$3.33 times 10^{14}$$ ppp, 1.16 sec)と大強度化する計画であり、不安定性をはじめとした集団効果によるビームロスの低減は必須である。大きなインピーダンスを持つと考えられている個々の装置のうち、FXセプタムとFXキッカーをCSTシミュレーションでモデル化し、縦および横方向のインピーダンスの見積もりを行った。特に大きな値となったインピーダンスについては、それが発生するウェイク場を減衰させる方法を検討した。FXセプタムについては、SiCをウェーク場の減衰器として追加することでインピーダンス低減を目指すように設計し、かつ発生する熱等が実用的かどうか調べ、製作を行なっている。インピーダンスの実測定は夏から秋に行う予定である。ここではシミュレーション過程およびインピーダンスのビームへの影響の見積りを報告する。


Quantitative and semi-quantitative analyses using a portable energy dispersive X-ray fluorescence spectrometer; Geochemical applications in fault rocks, lake sediments, and event deposits

渡邊 隆広; 石井 千佳子; 石坂 千佳; 丹羽 正和; 島田 耕史; 澤井 祐紀*; 土屋 範芳*; 松中 哲也*; 落合 伸也*; 奈良 郁子*

Journal of Mineralogical and Petrological Sciences, 116(3), p.140 - 158, 2021/00

 被引用回数:0 パーセンタイル:0.03(Mineralogy)

携帯型成分分析計(potable XRF:ポータブル蛍光エックス線分析装置)は、迅速な化学分析、及びオンサイトでのデータ取得において重要な役割を果たす。しかし、これまでに地質試料に含まれる化学成分の定量分析の実例は限られていた。定量分析を目的として、本研究ではマグネシウムからウランまでの24元素について、地球化学標準試料等を用いて検量線を作成した。さらに、本装置の天然試料への適用性評価のため、敦賀半島等から採取された断層岩試料,能登半島の湖底堆積物、及び仙台平野の津波堆積物の定量分析を実施した。携帯型成分分析計を用いて各試料から得られた定量分析結果は、一部の試料を除き既報値とよく一致した。


第2期中期計画期間における研究成果取りまとめ報告書; 深地層の研究施設計画および地質環境の長期安定性に関する研究

濱 克宏; 水野 崇; 笹尾 英嗣; 岩月 輝希; 三枝 博光; 佐藤 稔紀; 藤田 朝雄; 笹本 広; 松岡 稔幸; 横田 秀晴; et al.

JAEA-Research 2015-007, 269 Pages, 2015/08




Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency - Fusion Neutronics Source

篠原 孝司; 石井 啓一*; 落合 謙太郎; 馬場 護*; 助川 篤彦; 笹尾 眞實子*; 北島 純男*

Review of Scientific Instruments, 85(11), p.11E823_1 - 11E823_4, 2014/11

 被引用回数:0 パーセンタイル:0.01(Instruments & Instrumentation)

A neutron flux array is one of the important plasma diagnostics to obtain the information on fast ion population. However, the limited flux owing to its collimator results in the small number of pulse counts and the large statistical error. The method to increase the pulse counts is required. Here, we propose a multi-stage neutron detection system, in which several sets of a scintillator and photo-multiplier tube (PMT) are placed in a line-of-sight. In order to evaluate the performance of the multi-stage detection system, we have carried out experiments on a two-stage detection system using a neutron beam at FNS (Fusion Neutronics Source) of JAEA (Japan Atomic Energy Agency). The results have shown the concept of the multi-stage detection system works as expected. In the best setup, the test two-stage system reached about 1.7 (1.8) times the efficiency of a single scintillator and PMT system for 2.54 (14) MeV neutrons.


Construction of a 300-keV compact ion microbeam system with a three-stage acceleration lens

石井 保行; 大久保 猛; 小嶋 拓治; 神谷 富裕

Nuclear Instruments and Methods in Physics Research B, 332, p.156 - 159, 2014/08

 被引用回数:7 パーセンタイル:55.77(Instruments & Instrumentation)

A 300-keV compact ion microbeam system has been constructed to form a submicron ion microbeam. This system consists of a gas-ion source and a three-stage acceleration lens. Since the three-stage acceleration lens was designed to play two roles of acceleration and focusing for ion beam simultaneously, no focusing devices such as focusing lens and beam line are needed outside of the system. Therefore, the system is downsized to about 1 m high and can be placed in a small experimental room. The beam sizes formed by the system were experimentally measured by changing the voltages of the third acceleration lens in the three-stage acceleration lens within the range of 150 keV. These beam sizes were also theoretically calculated using Munro code. The experimentally obtained value was almost same of the theoretically estimated value. It demonstrated that the three-stage acceleration lens effectively worked on the focusing lens as designed.


Bipartite magnetic parent phases in the iron oxypnictide superconductor

平石 雅俊*; 飯村 壮史*; 小嶋 健児*; 山浦 淳一*; 平賀 晴弘*; 池田 一貴*; Miao, P.*; 石川 喜久*; 鳥居 周輝*; 宮崎 正範*; et al.

Nature Physics, 10(4), p.300 - 303, 2014/04

 被引用回数:94 パーセンタイル:96.38(Physics, Multidisciplinary)

High-temperature (high-$$T_{rm c}$$) superconductivity appears as a consequence of the carrier-doping of an undoped parent compound exhibiting antiferromagnetic order; thereby, ground-state properties of the parent compound are closely relevant to the superconducting state. On the basis of the concept, a spin-fluctuation has been addressed as an origin of pairing of the superconducting electrons in cuprates. Whereas, there is growing interest in the pairing mechanism such as an unconventional spin-fluctuation or an advanced orbital-fluctuation due to the characteristic multi-orbital system in iron-pnictides. Here, we report the discovery of an antiferromagnetic order as well as a unique structural transition in electron-overdoped LaFeAsO$$_{1-x}$$H$$_x$$ ($$x sim 0.5$$), whereby another parent phase was uncovered, albeit heavily doped. The unprecedented two-dome superconducting phases observed in this material can be interpreted as a consequence of the carrier-doping starting from the original at $$x sim 0$$ and advanced at $$x sim 0.5$$ parent phases toward the intermediate region. The bipartite parent phases with distinct physical properties in the second magnetic phase provide us with an interesting example to illustrate the intimate interplay among the magnetic interaction, structural change and orbital degree of freedom in iron-pnictides.



久語 輝彦; 石川 眞; 長家 康展; 横山 賢治; 深谷 裕司; 丸山 博見*; 石井 佳彦*; 藤村 幸治*; 近藤 貴夫*; 湊 博一*; et al.

JAEA-Research 2013-046, 53 Pages, 2014/03




Irradiation effect of swift heavy ion for Zr$$_{50}$$Cu$$_{40}$$Al$$_{10}$$ bulk glassy alloy

小野寺 直利*; 石井 顕人*; 石井 康嗣*; 岩瀬 彰宏*; 横山 嘉彦*; 齋藤 勇一; 石川 法人; 薮内 敦*; 堀 史説*

Nuclear Instruments and Methods in Physics Research B, 314, p.122 - 124, 2013/11

 被引用回数:3 パーセンタイル:29.69(Instruments & Instrumentation)



Research and development of neutron detection system using scintillator and digital-signal processing

篠原 孝司; 石井 啓一*; 落合 謙太郎; 馬場 護*; 笹尾 眞實子*; 北島 純男*

Plasma and Fusion Research (Internet), 8, p.1402144_1 - 1402144_9, 2013/11

A collimated neutron flux array system in JT-60U successfully upgraded performance of higher counting rate and the capability to detect 14 MeV neutrons as well by using a fast digitizer in 2006. Additionally, detailed analysis of the recorded waveform on JT-60U and FNS has provided us new findings. In this paper, firstly, characteristics of pulse shapes and neutron-$$gamma$$ discrimination parameters investigated by the detailed analysis of digitized waveform data are described. Next, new data analysis procedure for neutron-$$gamma$$ discrimination based on the characteristics is proposed. In the new procedure, an appropriate projection surface, on which we can define the discrimination boundary, has been introduced in three-dimensional discrimination parameter space. The problem of pulse height variation, which occurs when a counting rate is high in high performance plasma, and its countermeasures are also presented. The system using the countermeasure of a booster method successfully has avoided the problem in the high neutron flux condition of $$sim$$2$$times$$10$$^{5}$$ counts/s on FNS.


Hydrological gravity response detection using a gPhone below- and aboveground

田中 俊行*; 宮島 力雄*; 浅井 秀明*; 堀内 泰治; 熊田 宏治; 浅井 康広*; 石井 紘*

Earth Planets and Space, 65(2), p.59 - 66, 2013/02

 被引用回数:7 パーセンタイル:25.87(Geosciences, Multidisciplinary)

We used a gPhone (serial number 90), the newest spring-type gravimeter manufactured by Micro-g LaCoste Inc., to acquire high-quality, continuous gravity records, both below-and aboveground. At a depth of 100 m, when the gPhone was situated under an unconfined aquifer, the standard deviations of the residual gravity based on the first and second-order curve fittings were 4.2 and 2.7 $$mu$$Gal, respectively. Some gravity decreases caused by rainfall were clearly observed, but unknown gravity variations may also have occurred. Alternatively, when the gPhone was placed aboveground on the flank of a high mountain, the standard deviation of the residual gravity was 1.7 $$mu$$Gal for both the first-and second-order curve fittings. The rainfall amount and snow depth can explain most of the residual gravity. On the basis of these results, we propose to detect and correct hydrological gravity responses using multiple gravimeters to study gravity signals from deep within the earth.


Ground-state configuration of the $$N=157$$ nucleus $$^{259}$$No

浅井 雅人; 塚田 和明; 阪間 稔*; 羽場 宏光*; 市川 隆敏*; 石井 康雄; 豊嶋 厚史; 石井 哲朗; 西中 一朗; 永目 諭一郎; et al.

Physical Review C, 87(1), p.014332_1 - 014332_6, 2013/01

 被引用回数:4 パーセンタイル:36.33(Physics, Nuclear)



Design of a compact focusing lens system with short acceleration tube at 300 kV

石井 保行; 大久保 猛; 小嶋 拓治; 神谷 富裕

Nuclear Instruments and Methods in Physics Research B, 269(20), p.2193 - 2196, 2011/11

 被引用回数:9 パーセンタイル:62.21(Instruments & Instrumentation)

A high-demagnification acceleration lens system is developed for a compact apparatus forming gaseous ion nanobeam with an energy ranging from several hundred keV to MeV in Japan Atomic Energy Agency (JAEA). For gaseous ion nanobeam formation, it is necessary to use a plasma-type ion source. The diameter of the anode through-hole, which is an object in the lens system, in the ion source is several hundred micrometers to extract sufficient ion beams from ion source plasma. Therefore the lens system with the higher demagnification of over 1000 was required to form the nanobeam. In this study, the compact high-energy acceleration lens system up to several hundred keV was designed by combining the double acceleration-lens system already developed in JAEA to form several tens keV gaseous ion nanobeams and an acceleration tube newly designed in this study to boost up its beam energy. Especially since the acceleration tube plays roles of not only the ion beam acceleration but also a final focusing lens, the lens effect of its tube was studied in detail in the design. In the conference, the design of the new lens system based on the ion optical calculation and the specification of the whole system with a duoplasmatron-type ion source will be presented.


Three dimensional atomic image of TlInSe$$_{2}$$ by X-ray fluorescence holography

三村 功次郎*; 細川 伸也*; 八方 直久*; Hu, W.; 林 好一*; 脇田 和樹*; 石井 啓文*; 吉村 政人*; Jeyakanthan, J.*; Mamedov, N.*

e-Journal of Surface Science and Nanotechnology (Internet), 9, p.273 - 276, 2011/07

Three dimensional (3D) atomic images around the Tl atoms in single crystal TlInSe$$_{2}$$ thermoelectric material in the incommensurate phase were reconstructed by using Tl LIII X-ray fluorescence holography measured at room temperature. Comparison of the experimentally obtained 3D images with the theoretically calculated ones suggests that only the Tl atoms have large spatial fluctuations, which are related to the incommensurate phase of this material.


Three-dimensional atomic images of TlInSe$$_{2}$$ thermoelectric material obtained by X-ray fluorescence holography

細川 伸也*; 八方 直久*; 林 好一*; 三村 功次郎*; 脇田 和樹*; Hu, W.; 石井 啓文*; 吉村 政人*; Jeyakanthan, J.*; Mamedov, N.*

Japanese Journal of Applied Physics, 50(5), p.05FC06_1 - 05FC06_2, 2011/05

 被引用回数:6 パーセンタイル:30(Physics, Applied)

Three dimensional (3D) atomic images around the Tl atoms in single crystal TlInSe$$_{2}$$ thermoelectric material in the incommensurate phase were reconstructed by using Tl $$L$$$$_{rm III}$$ X-ray fluorescence holography measured at room temperature. In the obtained 3D image, the In atoms are clearly visible at the proper positions in the normal phase. However, the Tl atomic images are also observed but very weak. By comparing the experimental image with a theoretically calculated one, it is concluded that only the Tl atoms have large spatial fluctuations, which are related to the incommensurate phase of this material.


Neutron one-quasiparticle states in $$^{251}$$Fm$$_{151}$$ populated via the $$alpha$$ decay of $$^{255}$$No

浅井 雅人; 塚田 和明; 羽場 宏光*; 石井 康雄; 市川 隆敏*; 豊嶋 厚史; 石井 哲朗; 永目 諭一郎; 西中 一朗; 小島 康明*; et al.

Physical Review C, 83(1), p.014315_1 - 014315_12, 2011/01

 被引用回数:19 パーセンタイル:76.34(Physics, Nuclear)



Fast neutron-$$gamma$$ discrimination on neutron emission profile measurement on JT-60U

石井 啓一*; 篠原 孝司; 石川 正男; 馬場 護*; 磯部 光孝*; 岡本 敦*; 北島 純男*; 笹尾 眞實子*

Review of Scientific Instruments, 81(10), p.10D334_1 - 10D334_3, 2010/10

 被引用回数:6 パーセンタイル:33.58(Instruments & Instrumentation)

Automatic analysis of the neutron-$$gamma$$ pulse shape discrimination has been developed for the neutron emission profile monitor, which uses stilbene scintillation detectors, in JT-60U. In the automatic analysis, linear discriminant function is applied to determine the line dividing between neutron events and $$gamma$$-ray events on the 2D map. In order to verify the validity of the determined line, the pulse shape discrimination quality is evaluated with the ratio of $$gamma$$-ray events to neutron events, namely contamination by $$gamma$$-ray. As a result, it is clear that $$gamma$$-ray contamination is below to statistical error with the time resolution of 10 ms.


Beam injection tuning of the J-PARC main ring

Wei, G.; 小関 忠*; 五十嵐 進*; 冨澤 正人*; 高野 淳平*; 石井 恒次*; 白形 政司*; Fan, K.*; 畠山 衆一郎; 魚田 雅彦*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3915 - 3917, 2010/05

The beam commissioning of J-PARC (Japan Proton Accelerator Research Complex) MR (Main Ring) was started from May 2008 and is in progress. As usual, injection tuning is in the first stage and strongly related to other tuning items. Starting with design schemes, making adjustment due to leakage field influence from injection septum, doing envelope matching considering dilution of beam profile in Main Ring are reported in this papers.


Beam fast extraction tuning of the J-PARC main ring

Wei, G.; 小関 忠*; 冨澤 正人*; 五十嵐 進*; 石井 恒次*; 安東 愛之輔; 高野 淳平*; 魚田 雅彦*; Fan, K.*; 畠山 衆一郎; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3918 - 3920, 2010/05

The beam commissioning of J-PARC/MR has been started from May 2008 and is in good progress. One key purpose of MR commissioning is the 30 GeV beam fast extraction to neutrino beam line, which reflect the overall commissioning result. In the MR, fast extraction system comprises 5 kickers and 8 septa which give a bipolar kick to neutrino beam line or abort dump. However before commissioning, the measured magnetic field distribution of each fast extraction septa shows non-linear profile along the horizontal direction. In order to find the influence, a beam simulation with the measured field distributions of septa has been performed. Depends on this study and some OPI (Operation Interface) made by code SAD for orbit modification online, fast extraction of 30 GeV beam to neutrino beam line has been achieved on April 23rd 2009. And so far, 100 kW continual operation to neutrino line have been achieved, too.


The Present status of TIARA at JAEA-Takasaki

齋藤 勇一; 横田 渉; 奈良 孝幸; 上松 敬; 奥村 進; 宇野 定則; 石堀 郁夫; 倉島 俊; 吉田 健一; 湯山 貴裕; et al.

Proceedings of the 8th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-8), p.95 - 98, 2008/12

The accelerators at TIARA of Japan Atomic Energy Agency are dedicated to researches in the field of biotechnology and material science. These researches require beams of various ion species covering a wide range of energy and a number of different methods of irradiation. In order to satisfy the requirements, outstanding technologies such as microbeam formation and wide-area high-uniformity irradiation have been developed as well as accelerator technologies. The paper describes the major accelerator/ beam formation/ irradiation technologies developed in recent years.


$$Q_{beta}$$ measurements of $$^{158,159}$$Pm, $$^{159,161}$$Sm, $$^{160-165}$$Eu, $$^{163}$$Gd and $$^{166}$$Tb using a total absorption BGO detector

林 裕晃*; 秋田 幸範*; 末松 倫*; 柴田 理尋*; 浅井 雅人; 佐藤 哲也; 市川 進一; 西中 一朗; 永目 諭一郎; 長 明彦; et al.

European Physical Journal A, 34(4), p.363 - 370, 2007/12

 被引用回数:16 パーセンタイル:72.91(Physics, Nuclear)

全吸収BGO検出器を用いて$$^{160-165}$$Euと$$^{163}$$Gdの$$Q_{beta}$$を初めて測定し、また過去に測定した$$^{158,159}$$Pm, $$^{159,161}$$Sm, $$^{166}$$Tbのデータを再解析した。これらの核種は、原子力機構東海タンデム加速器施設において$$^{238}$$Uの陽子誘起核分裂で合成し、オンライン同位体分離装置を用いて核反応生成物の中から分離した。得られた質量偏差と2中性子分離エネルギーの値を、原子質量評価値や理論計算の値と比較した。

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