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Compton scattering of quasi-monochromatic $$gamma$$-ray beam

Omer, M.; 静間 俊行*; 羽島 良一*

Nuclear Instruments and Methods in Physics Research A, 951, p.162998_1 - 162998_6, 2020/01

Compton scattering of a single-energy $$gamma$$-ray results in a one-to-one relationship between the incident and scattered photon energies. This relationship is altered when the incident beam has a definite energy distribution because of the broadening occurring in the energy distribution upon Compton scattering. This broadening causes a change in the spectral density of the Compton-scattered spectra. To restore the spectral density, the energy distribution of the scattered radiation must be manifested as a function of the scattering kinematics. Here, we propose a simple analytic way to calculate the energy spread of the scattered photons in terms of the geometry of the scattering process and the energy spread of the incident photon beam. The predictions of the model agree with measurements of Compton scattering of quasi-monochromatic $$gamma$$-ray beams, carried out at the High Intensity $$gamma$$-ray Source (HI$$gamma$$S) facility, Duke University. As a benchmark of our method, we measured the intensity profile of energy-distributed $$gamma$$-ray beams by direct measurements as well as by Compton scattering. We found that only when the spectral density of the scattered radiation is restored, the measured intensity profile agrees with the actual profile of the incident beam. The proposed method can continuously measure the flux of an energy-distributed $$gamma$$-ray beams in the real time and on a bin-by-bin basis. Such online monitoring of $$gamma$$-ray beams is indispensable for in-beam measurements and applications. This work was supported by the subsidiary for promotion of strengthening nuclear security or the like of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan.


Depth profiles of energy deposition near incident surface irradiated with swift heavy ions

小川 達彦; 石川 法人; 甲斐 健師

Nuclear Instruments and Methods in Physics Research B, 461, p.272 - 275, 2019/12



Control of the size of etchable ion tracks in PVDF; Irradiation in an oxygen atmosphere and with fullerene C$$_{60}$$

喜多村 茜; 八巻 徹也*; 百合 庸介*; 越川 博*; 澤田 真一*; 湯山 貴裕*; 薄井 絢; 千葉 敦也*

Nuclear Instruments and Methods in Physics Research B, 460, p.254 - 258, 2019/12



FE-SEM observation of chains of nanohillocks in SrTiO$$_{3}$$ and Nb-doped SrTiO$$_{3}$$ surfaces irradiated with swift heavy ions

喜多村 茜; 石川 法人; 近藤 啓悦; 山本 春也*; 八巻 徹也*

Nuclear Instruments and Methods in Physics Research B, 460, p.175 - 179, 2019/12



Ion-induced irradiation hardening of the weld heat-affected zone in low alloy steel

河 侑成; 高見澤 悠; 勝山 仁哉; 塙 悟史; 西山 裕孝

Nuclear Instruments and Methods in Physics Research B, 461, p.276 - 282, 2019/12

The microstructural distribution in the heat-affected zone (HAZ) under the stainless overlay cladding of low alloy steel was investigated by metallurgical observation and finite element analysis (FEA). The distribution of the coarse-grain (CG) HAZ and the fine-grain (FG) HAZ in low alloy steel by metallurgical observation agreed well with the FEA results. Base metal contained mixed bainite with ferrite, whereas the CGHAZ and the FGHAZ contained mixed lower bainite with martensite and mixed upper bainite with ferrite, respectively. Ferrite fraction in FGHAZ was higher than those other areas. After ion irradiation at a fluence of 0.5 dpa, irradiation hardening and the formation of solute clusters were observed at the base metal, FGHAZ, and the CGHAZ. Atom probe tomography analysis revealed that irradiation hardening increased with increasing volume fraction of clusters, although irradiation hardening at the FGHAZ was greater than that at the CGHAZ, which contained more clusters than the FGHAZ. This difference in irradiation hardening may be due to the differences in the amount of ferrite, carbide precipitates and so on in the different microstructures.


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

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

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.


Ion beam induced luminescence of complexes formed in adsorbent for MA recovery process

渡部 創; 片井 雄也*; 松浦 治明*; 加田 渉*; 江夏 昌志*; 佐藤 隆博*; 新井 剛*

Nuclear Instruments and Methods in Physics Research B, 450, p.61 - 65, 2019/07

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

Ion-beam induced luminescence (IBIL) analysis on MA recovery adsorbent was performed to give chemical states of complexes formed in the adsorbent as fundamental information for process design, and EXAFS analysis was also carried out to support discussions. The IBIL spectra of the binary extractants system seemed to be superposition of individual ones, however it has also original peaks. As intensities of those peaks rapidly decreased with iteration time of measurements and the original peaks were not observed for the adsorbent without charging Eu(III), they were attributed to complexes of Eu(III) with organic compounds. Contributions of CMPO and HDEHP extractants for Eu(III) extraction must be not only individual ones but also cooperative.


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

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

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

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

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。


Recent progress in QCD condensate evaluations and sum rules

Gubler, P.; 佐藤 大輔*

Progress in Particle and Nuclear Physics, 106, p.1 - 67, 2019/05

 被引用回数:5 パーセンタイル:3.99(Physics, Nuclear)



Studies of extremely dense matter in heavy-ion collisions at J-PARC

佐甲 博之

Nuclear Physics A, 982, p.959 - 962, 2019/02

 被引用回数:0 パーセンタイル:100(Physics, Nuclear)

We aim to study extremely dense matter in heavy-ion collisions at 1-19 AGeV/c at a future project of J-PARC (JPARC-HI). We will search for the first order phase boundary and its critical end point in the QCD phase diagram. We also aim at studying the properties of dense matter related to neutron stars and neutron star mergers, in particular the equation of state (EOS). We expect to produce world's highest rate heavy-ion beams of $$10^{11}$$ with the ion species from p to U. We design spectrometers based on a large dipole magnet to measure hadrons, dimuons, and hypernuclei. We evaluate some of key performance of the spectrometers based on detailed simulations.


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

 被引用回数:0 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

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



Influence of gamma-ray irradiation on mechanical property of YSZ for oxygen sensors in ADS

大久保 成彰; 奥野 泰希; 喜多村 茜; 田口 富嗣*

Nuclear Instruments and Methods in Physics Research B, 435, p.198 - 202, 2018/11

原子力機構で開発を進めている加速器駆動核変換システム(ADS)では、冷却材及び核破砕ターゲットとして液体鉛ビスマス共晶合金(LBE)を用いる。ADSでは、LBE中の酸素制御が重要な技術開発項目である。酸素センサ素子にはイットリア添加ジルコニア(YSZ)が用いられるが、ADSでは、放射化したLBEから$$gamma$$線照射を受けるため、$$gamma$$線照射環境下での酸素センサの信頼性評価が必要である。本報告では、各種YSZの強度特性に及ぼす$$gamma$$線照射の影響を調べた。イットリア添加濃度を3, 6, 8mol%と変えた3種類のYSZ曲げ試験片に対して、実機1年間運転後のLBEから受ける$$gamma$$線量に相当する1及び2kGy/hの線量率にて、$$gamma$$線照射を行った。照射後に、4点曲げ試験, XRD, SEM観察及びラマン分光による評価を行い、以下の結果を得た。8Y, 6Yでは、$$gamma$$線照射による強度変化や破面の形態変化は見られず、一方、3Yでは、XRDにより、強度変化に影響を及ぼすほどではないが、照射量に依存した、正方晶から単斜晶への相変態を示す結果が得られた。これは、$$gamma$$線照射により予め相変態が誘起されたことを示し、ラマン分光測定によっても、相変態を示す結果が得られた。


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

 被引用回数:1 パーセンタイル:55.09(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

 被引用回数:1 パーセンタイル:55.09(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:17.17(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

 被引用回数:2 パーセンタイル:30.45(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

 被引用回数:4 パーセンタイル:10.32(Instruments & Instrumentation)

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

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


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