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Performance of large volume LaBr$$_{3}$$ scintillation detector equipped with specially-designed shield for neutron resonance capture analysis

土屋 晴文; 小泉 光生; 北谷 文人; 原田 秀郎

Nuclear Instruments and Methods in Physics Research A, 932, p.16 - 26, 2019/07

A large-volume ($$phi$$12.0 cm$$times$$12.7 cm) LaBr$$_{3}$$ scintillation detector equipped with a specially-designed radiation shield was evaluated for neutron resonance capture analysis at the neutron time-of-flight (TOF) facility GELINA. By using the LaBr$$_{3}$$ detector with and without the shield, measurements were carried out at a 13-m TOF station with three metallic samples, namely, Ni, Cr, and Fe. In addition, Monte Carlo simulations with Geant4 were performed, and the results were compared with the measurements to analyze the observed energy spectra and TOF spectra. Energy spectra obtained with the shield showed that prompt $$gamma$$-ray peaks emitted from each sample can be used to identify the isotopes. Moreover, the signal-to-noise ratios of resonance peaks in a TOF spectrum with the shield were enhanced 1.5-2.5 in comparison with those without the shield. Furthermore, simultaneous measurements conducted using the three samples demonstrated that the shield employed herein was indispensable for identifying impurities in a composite sample such as particle-like fuel debris.


Measurement of neutron scattering cross section of nano-diamond with particle diameter of approximately 5 nm in energy range of 0.2 meV to 100 meV

勅使河原 誠; 土川 雄介*; 市川 豪*; 高田 慎一; 三島 賢二*; 原田 正英; 大井 元貴; 河村 幸彦*; 甲斐 哲也; 河村 聖子; et al.

Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06

ナノダイアモンドは、冷中性子以下のエネルギーにおける反射材として注目されている。ナノダイアモンドを用いた中性子源の高度化には、断面積データの整備が必要である。そのため、この論文では、中性子の透過率の測定から0.2meVから100meVの範囲で全断面積を測定した結果を報告する。測定した全断面積は、エネルギーが低くなるにつれて大きくなり、グラファイトと比較すると0.2meVで約2桁以上高くなることが分かった。その全断面積に占める非弾性散乱の寄与を調べるため、中性子のエネルギー1.2, 1.5, 1.9及び5.9meVで中性子非弾性散乱実験を行った。その結果、測定したエネルギーにおいて、全断面積に占める非弾性散乱の寄与がほぼ無視できることも分かった。さらに、中性子小角散乱実験の結果から、全断面積の高くなる要因として、前方方向、いわゆる小角方向への散乱の寄与が高いことが示された。


Thick target neutron yields from 100- and 230-MeV/nucleon helium ions bombarding water, PMMA, and iron

Tsai, P.-E.; Heilbronn, L. H.*; Lai, B.-L.*; 岩田 義之*; 村上 武*; Sheu, R.-J.*

Nuclear Instruments and Methods in Physics Research B, 449, p.62 - 70, 2019/06

100および230MeV/核子のヘリウムイオンが厚い鉄, PMMA,水ターゲットで止まった際に放出される二次中性子について波形弁別法と飛行時間法を用いて液体シンチレータで測定した。測定値を分析したところ、二次中性子は入射粒子の破砕、入射粒子と標的原子核の重複部からの放出、標的核の蒸発の成分に分類できることが分かった。測定された中性子収量の二重微分,角度微分,生成総量については、PHITS, FLUKA, MCNPの各計算コードのベンチマークに使用した。デフォルトのモデルを使用したこれらのコードの計算値は、低中エネルギーで中大角度に放出された場合の、実験値とよく一致した。一方、PHITSの核反応モデルは一部の核反応メカニズムで改善が必要なことも見いだされ、本実験結果はモデル改良にとって重要な参考データとなる。


Radiocarbon variations in tree rings since 1960 near the Tokai nuclear facility, Japan

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

Nuclear Instruments and Methods in Physics Research B, 439, p.64 - 69, 2019/01

 パーセンタイル:100(Instruments & Instrumentation)



Applications of ion channeling in accelerator mass spectrometry

松原 章浩*; 藤田 奈津子; 石井 邦和*

Nuclear Instruments and Methods in Physics Research B, 437, p.81 - 86, 2018/12

 パーセンタイル:100(Instruments & Instrumentation)



Fluoropolymer-based nanostructured membranes created by swift-heavy-ion irradiation and their energy and environmental applications

八巻 徹也*; Nuryanthi, N.*; 喜多村 茜; 越川 博*; 澤田 真一*; Voss, K.-O.*; Severin, D.*; Tautmann, C.*

Nuclear Instruments and Methods in Physics Research B, 435, p.162 - 168, 2018/11

 パーセンタイル:100(Instruments & Instrumentation)



A New detector system for the measurement of high-energy prompt $$gamma$$-rays for low-energy neutron induced fission

牧井 宏之; 西尾 勝久; 廣瀬 健太郎; Orlandi, R.; L$'e$guillon, R.*; 小川 達彦; Soldner, T.*; Hambsch, F.-J.*; A$"i$che, M.*; Astier, A.*; et al.

Nuclear Instruments and Methods in Physics Research A, 906, p.88 - 96, 2018/10

 パーセンタイル:100(Instruments & Instrumentation)



Experimental validation of the brightness distribution on the surfaces of coupled and decoupled moderators composed of 99.8% parahydrogen at the J-PARC pulsed spallation neutron source

原田 正英; 勅使河原 誠; 大井 元貴; Klinkby, E.*; Zanini, L.*; Batkov, K.*; 及川 健一; 藤 暢輔; 木村 敦; 池田 裕二郎

Nuclear Instruments and Methods in Physics Research A, 903, p.38 - 45, 2018/09

 被引用回数:3 パーセンタイル:7.87(Instruments & Instrumentation)

At the J-PARC pulsed spallation neutron source, liquid hydrogen moderators composed of 99.8% parahydrogen associated with light-water premoderator have been providing high intensity cold and thermal neutron beams. In the design stage, simulations have shown not only high total neutron intensity in the coupled moderator but also a local neutron-brightness increase at the edges. The edge-effect-brightness increase is also exploited in the design of the European Spallation Source (ESS) moderators, which are based on 99.8% parahydrogen, but thin (thickness: 3 cm) to enhance the neutron brightness. In this study, the spatial distribution of the neutron brightness at the surface of the coupled moderator in the J-PARC pulsed spallation neutron source was directly measured with the pinhole geometry to validate the calculated edge-brightness enhancement. The brightness distribution at the moderator surface was clearly observed as predicted by a Monte Carlo simulation, proving the validity of the simulation tools used in the design-optimization process of the J-PARC and ESS moderator.


Development of high-polarization Fe/Ge neutron polarizing supermirror; Possibility of fine-tuning of scattering length density in ion beam sputtering

丸山 龍治; 山崎 大; 阿久津 和宏*; 花島 隆泰*; 宮田 登*; 青木 裕之; 武田 全康; 曽山 和彦

Nuclear Instruments and Methods in Physics Research A, 888, p.70 - 78, 2018/04

 パーセンタイル:100(Instruments & Instrumentation)



Experimental setup and procedure for the measurement of the $$^7$$Be(n,p)$$^7$$Li reaction at n_TOF

Barbagallo, M.*; Andrzejewski, J.*; Mastromarco, M.*; Perkowski, J.*; Damone, L. A.*; Gawlik, A.*; 木村 敦; n_TOF Collaboration*; 他122名*

Nuclear Instruments and Methods in Physics Research A, 887, p.27 - 33, 2018/04

Following the completion of the second neutron beam line and the related experimental area (EAR2) at the n_TOF spallation neutron source at CERN, several experiments were planned and performed. The high instantaneous neutron flux available in EAR2 allows to investigate neutron induced reactions with charged particles in the exit channel even employing targets made out of small amounts of short-lived radioactive isotopes. After the successful measurement of the $$^7$$Be(n,$$alpha$$)cross section, the $$^7$$Be(n,p)$$^7$$Li reaction was studied in order to provide still missing cross section data of relevance for Big Bang Nucleosynthesis (BBN), in an attempt to find a solution to the cosmological Lithium abundance problem. This paper describes the experimental setup employed in such a measurement and its characterization.


Implementing displacement damage calculations for electrons and $$gamma$$ rays in the Particle and Heavy-Ion Transport code System

岩元 洋介

Nuclear Instruments and Methods in Physics Research B, 419, p.32 - 37, 2018/03

 パーセンタイル:100(Instruments & Instrumentation)



Benchmark of neutron production cross sections with Monte Carlo codes

Tsai, P.-E.; Lai, B.-L.*; Heilbronn, L. H.*; Sheu, R.-J.*

Nuclear Instruments and Methods in Physics Research B, 416, p.16 - 29, 2018/02

 パーセンタイル:100(Instruments & Instrumentation)

薄膜ターゲットを用いた15種類の照射条件について、中性子生成断面積のベンチマークを実施した。条件は、核子当たり135$$sim$$600MeVの$$^{12}$$C, $$^{20}$$Ne, $$^{40}$$Ar, $$^{84}$$Kr, $$^{132}$$Xeイオン照射、$$^{nat}$$Li, $$^{nat}$$C, $$^{nat}$$Al, $$^{nat}$$Cu, $$^{nat}$$Pbターゲットを組み合わせたものである。実験値を4つのシミュレーション法(1)PHITS 2.73 (JQMDとGEMモデル)、(2)PHITS 2.82 (JQMD 2.0とGEMモデル)、(3)FLUKA 2011.2c (RQMD 2.4とFLUKA脱励起モデル)、及び(4)MCNP6-1.0 (LAQGSM 03.03とGEM2モデル)による結果と比較した。本研究は計算コードユーザーだけでなく、PHITS-JQMDモデル開発者にとっても有益な情報をもたらすものであり、加速器施設安全や重粒子線治療、宇宙放射線科学の発展に資する将来の重イオン核反応物理モデルの改良へも寄与するものである。


The Laser and optical system for the RIBF-PALIS experiment

園田 哲*; 飯村 秀紀; Reponen, M.*; 和田 道治*; 片山 一郎*; Sonnenschein, V.*; 高松 峻英*; 富田 英生*; 小島 隆夫*

Nuclear Instruments and Methods in Physics Research A, 877, p.118 - 123, 2018/01

 被引用回数:2 パーセンタイル:16.17(Instruments & Instrumentation)



Systematic effects on cross section data derived from reaction rates in reactor spectra and a re-analysis of $$^{241}$$Am reactor activation measurements

$v{Z}$erovnik, G.*; Schillebeeckx, P.*; Becker, B.*; Fiorito, L.*; 原田 秀郎; Kopecky, S.*; Radulovic, V.*; 佐野 忠史*

Nuclear Instruments and Methods in Physics Research A, 877, p.300 - 313, 2018/01

 被引用回数:1 パーセンタイル:38.14(Instruments & Instrumentation)



Measurement of thermal deformation of magnetic alloy cores of radio frequency cavities in 3-GeV rapid-cycling synchrotron of Japan Proton Accelerator Research Complex

島田 太平; 野村 昌弘; 田村 文彦; 山本 昌亘; 杉山 泰之*; 大森 千広*; 長谷川 豪志*; 原 圭吾*; 吉井 正人*

Nuclear Instruments and Methods in Physics Research A, 875, p.92 - 103, 2017/12

 パーセンタイル:100(Instruments & Instrumentation)

Magnetic alloy cores loaded in radio frequency cavities are employed to achieve a high field gradient in the 3-GeV Rapid-Cycling Synchrotron of the Japan Proton Accelerator Research Complex. We use three core-types, which were manufactured in three different processes. Buckling occurred in some cores of only one of the three core types. In order to find out the mechanism of buckling, we measured thermal deformations of the two core types, which had not buckled and the core types, which had buckled, while changing their temperatures by RF heating in air. Furthermore, we calculated the thermal stress using the results of the experiments. These experiments yielded that there was no remarkable difference in the strength of thermal stress between the core types, which had not buckled, and the core types, which had buckled; however, that there was a clear difference in the behavior of thermal deformations. The local deformations appeared, when a certain temperature was exceeded, and accelerated with temperature rise in the buckled core types. This was not seen with core types that didn't show the buckling problem. We conclude that the repetition of these catastrophic and local deformations, which are accelerated with the temperature rises, lead to the buckling. This result contributes to the stable operation of RCS.


Temperature of thermal spikes induced by swift heavy ions

松崎 勝太*; 林 宏明*; 中嶋 薫*; 松田 誠; 左高 正雄*; 辻本 将彦*; Toulemonde, M.*; 木村 健二*

Nuclear Instruments and Methods in Physics Research B, 406(Part B), p.456 - 459, 2017/09

Few-nm sized gold, platinum and palladium nanoparticles were deposited on amorphous silicon nitride films. These films were irradiated with 420 MeV Au and 100 MeV Xe ions. Temperature distributions of thermal spikes produced by these ions were evaluated by observing desorption of the nanoparticles from the target surfaces upon ion impact. It was found that the temperature of the thermal spike produced by 420 MeV Au is higher than 100 MeV Xe. The observed temperature of the thermal spike at the entrance surface is slightly lower than that at the exit surface both for 420 MeV Au and 100 MeV Xe ions. These results can be well explained by the inelastic thermal spike model.


Local structure and distribution of remaining elements inside extraction chromatography adsorbents

渡部 創; 佐野 雄一; 塩飽 秀啓; 矢板 毅; 大野 真平*; 新井 剛*; 松浦 治明*; 江夏 昌志*; 佐藤 隆博*

Nuclear Instruments and Methods in Physics Research B, 404, p.202 - 206, 2017/08

 パーセンタイル:100(Instruments & Instrumentation)

Extraction chromatography is one of the most promising technology for minor actinide (MA(III): Am and Cm) recovery from high level liquid waste generated in the reprocessing. A brand-new adsorbent proposed by our group are expected to achieve more efficient MA(III) recovery than usual procedure. Fundamental MA(III) adsorption/elution performances of the adsorbents have been demonstrated. An appropriate washing process of lanthanides (Ln(III)) is necessary to be established to design a process flow. In this study, chemical state and distribution of Eu inside the adsorbent before and after contacting with candidate eluents for MA(III) or Ln(III) were evaluated by EXAFS measurements and micro-PIXE analysis, respectively. Two-dimensional PIXE images showed that adsorbed Eu and residual Eu after contacting with the eluents for MA(III) were uniformly distributed on the particle. However, EXAFS oscillation revealed that local structure around Eu drastically changes by the contact. Those results suggest that the Eu remained inside the particle without distinct shift and that they form various complexes with extractants in the particle.


Including Delbr$"u$ck scattering in GEANT4

Omer, M.; 羽島 良一*

Nuclear Instruments and Methods in Physics Research B, 405, p.43 - 49, 2017/08

 被引用回数:1 パーセンタイル:64.68(Instruments & Instrumentation)



Microscopic analyses of complexes formed in adsorbent for Mo and Zr separation chromatography

安倍 諒治*; 名越 航平*; 新井 剛*; 渡部 創; 佐野 雄一; 松浦 治明*; 高木 秀彰*; 清水 伸隆*; 江夏 昌志*; 佐藤 隆博*

Nuclear Instruments and Methods in Physics Research B, 404, p.173 - 178, 2017/08

 パーセンタイル:100(Instruments & Instrumentation)

Molybdenum and zirconium obstruct the efficient recovery of minor actinides (MA(III): Am(III) and Cm(III)) by extraction chromatography; hence, the removal of these elements prior to MA(III) recovery is desirable. The use of an adsorbent impregnated with bis(2-ethylhexyl) hydrogen phosphate (HDEHP) for Mo and Zr decontamination was evaluated in this report. The adsorption/elution and column separation experiments showed that Mo and Zr in the simulated HLLW were selectively adsorbed on the particles, and that Mo was eluted by H$$_{2}$$O$$_{2}$$. EXAFS analysis and SAXS patterns of the adsorbent containing Zr revealed that the Zr-HDEHP complex had a crystal-like periodic structure similar to the structure of the precipitate produced in the solvent extraction system. Micro-PIXE analysis revealed that distribution of the residual Zr on the adsorbent was uniform.


Simultaneous measurement of neutron-induced fission and capture cross sections for $$^{241}$$Am at neutron energies below fission threshold

廣瀬 健太郎; 西尾 勝久; 牧井 宏之; 西中 一朗*; 太田 周也*; 永山 達郎*; 田村 信行*; 後藤 真一*; Andreyev, A.; Vermeulen, M. J.; et al.

Nuclear Instruments and Methods in Physics Research A, 856, p.133 - 138, 2017/06

 被引用回数:3 パーセンタイル:27.27(Instruments & Instrumentation)

Fission and capture reactions were simultaneously measured in the neutron-induced reactions of $$^{241}$$Am at J-PARC. Data were taken with the TOF method in $$E_n$$ = 0.1$$sim$$20 eV. The fission events were observed by detecting prompt fission neutrons using liquid organic scintillators. The capture reaction was measured by detecting $$gamma$$ rays from the compound nuclei using the same detectors, where the prompt fission neutrons and capture $$gamma$$ rays were separated by a pulse shape analysis. The cross sections were obtained by normalizing the relative yields at the first resonance to evaluations or other experimental data. The ratio of the fission to capture cross sections at each resonance is compared with those from an evaluated nuclear data library and other experimental data. Some differences were found between the present values and the library/literature values at several resonances.

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