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Cd
廣瀬 雄介; 土塔 寛*; 竹内 徹也*; 三宅 厚志*; 徳永 将史*; 仲村 愛*; 本間 佳哉*; 青木 大*; 本多 史憲*; 摂待 力生*
Journal of Physics; Condensed Matter, 38(24), p.245601_1 - 245601_11, 2026/06
被引用回数：0 パーセンタイル：0.00(Physics, Condensed Matter)The electronic state of UPdCd, which exhibits a magnetic transition at 
5 K, is investigated by means of transport, high-field magnetization up to 55 T, specific heat in magnetic fields, and de Haas-van Alphen (dHvA) measurements, and compared with the non-5f compound ThPdCd. A metamagnetic transition is observed at 
15-20 T, which continuously connects to in the H-T phase diagram. Although the magnetization reaches large values at high fields, the ordered magnetic moment is estimated to be small from small anomalies in specific heat at and in magnetization at 
. The observed dHvA frequencies reveal enhanced cyclotron effective masses of 30 
, which are much heavier than those in ThPdCd. These experimental results indicate that 5f-derived bands contribute to the large electronic specific heat coefficient of 670 mJ/mol K
, demonstrating the dual localized-itinerant character of 5f electrons in UPdCd.
Cd廣瀬 雄介; 本多 史憲*; 土塔 寛*; 河村 直己*; Kvashnina, K. O.*; Amidani, L.*; Uhl
ov
, K.*; Koloren
, J.*; Havela, L.*
Physical Review B, 113(24), p.L241103_1 - L241103_6, 2026/06
被引用回数：1 パーセンタイル：82.33(Materials Science, Multidisciplinary)The regime of valence fluctuations, known from anomalous rare-earth systems with slow fluctuations between two different fn states, has not yet been identified by microscopic techniques at any Uranium compound. The reason may be in the predominant band character of U intermetallic compounds. Here we present U-L3 and M4 X-ray absorption spectra taken on UPdCd, which is a heavy-Fermion antiferromagnet. Although it has only one type of U site, the spectra obtained in the High Energy Resolution Fluorescence Detection mode display two edges, each associated with different valence states, 5f2 and 5f3. This is strongly suggestive of slow f2 - f3 fluctuations on the timescale longer than the characteristic time of the spectroscopy technique. Unlike 4f systems in which such fluctuations lead to a destruction of magnetism due to involvement of one non-magnetic state, the f2 and f3 states in U are both possibly magnetic, allowing for the magnetic ordering in the fluctuating state. Such a new situation can bring more light into emergent phenomena observable in U systems at the verge of 5f localization.
In
( = Co, Rh, Ir)栗原 綾輔*; 廣瀬 雄介; 松井 一樹*; 三宅 厚志*; 角田 竜馬*; 近藤 雅起*; 摂待 力生*; 赤津 光洋*; 根本 祐一*; 矢口 宏*; et al.
JJAP Conference Proceedings (Internet), 12, p.011006_1 - 011006_6, 2026/02
強磁場における量子限界状態では、電子相関や電子格子相互作用に由来する新奇な電子状態が提案されている。本研究では、7Tという比較的低磁場で量子限界に達すると考えられているLaRhIn及び関連物質LaIn (T:遷移金属)を対象とし、強磁場での超音波測定を行った。音響ドハース振動から、先行研究と同様のLaRhInの小さなフェルミ面を観測し、T=CoおよびIrでも量子振動がみられこれまで観測されていなかった100T以下の小さなフェルミ面の存在を明らかにした。遷移金属の
電子が小さなフェルミ面への寄与を示唆する結果であった。
N(
,
)
O reaction rates via the 
F(,
)
F reactionKim, S. H.*; Chae, K. Y.*; 浅井 雅人; 廣瀬 健太郎; 佐藤 哲也; 牧井 宏之; 西尾 勝久; Orlandi, R.; Smallcombe, J.; 洲嵜 ふみ; et al.
Journal of the Korean Physical Society, 6 Pages, 2026/00
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)コア崩壊超新星爆発(CCSNe)の元素合成シミュレーションにおいて、N(,)O反応速度の不確実性が課題となっていた。本研究では、この反応を制約するため、JAEAタンデム加速器でF(,)F遷移反応実験を実施した。得られたトリトンスペクトルと角度分布から、関連するF共鳴の崩壊特性(部分幅)を詳細に測定し、その結果を用いて反応速度パラメータを精密化した。これにより、CCSNe核合成モデルの信頼性向上が期待できる。
Ti
)
NiSe
土田 駿*; 廣瀬 雄介; 関川 卓也; 大野 義章*; 平原 卓也*; 佐野 純佳*; 河口 彰吾*; 小林 慎太郎*; 上床 美也*; 摂待 力生*
Journal of the Physical Society of Japan, 94(11), p.114703_1 - 114703_7, 2025/10
被引用回数：2 パーセンタイル：37.78(Physics, Multidisciplinary)本研究では、励起子絶縁体TaNiSeへのキャリアドープ効果を調べるために、(TaTi)NiSeの単結晶合成し、電気抵抗
ホール係数
およびバンド計算を行った。TaサイトのTi元素置換により、結晶構造は変化せず励起子絶縁体転移温度
は連続的に抑制され
=0.104で83Kまで抑制された。置換量を増やしていくと、半導体的なやの低温での増大が著しく抑制され、
では金属的な振る舞いに変わることを見出し、励起子相関のある金属状態が実現されている可能性がある。この金属化はバンド計算により、キャリアドーピング効果によって説明できる。このキャリアドープ物質を加圧していくと、2.6GPa以上で超伝導となることを明らかにした。この圧力は母物質TaNiSeの圧力誘起超伝導が現れる8GPaよりもはるかに小さく、Ti置換によるキャリアドープが超伝導に有利に働いたと考えられる。
高木 慎弥*; 原田 壮太*; 有友 嘉浩*; 廣瀬 健太郎; 西尾 勝久
Physical Review C, 112(4), p.044607_1 - 044607_9, 2025/10
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)Actinide nucleus shows mass-asymmetric fission in low energy due to shell structure. The fission fragment mass distributions at high energy tend to have a symmetric shape due to smearing of the shell. On the other hand, the distribution can be changed by the neutron emission before fission, as it decreases the excitation energy of fissioning nucleus, thus revives the shell structure. In the so called multichance fission, neutron emission is considered at the ground state shape, and competition between fission and neutron emission is determined in the framework of statistical model. In the present work, we describe fission in the Langevin equations, and the neutron emission is treated all over the fission process. The calculation demonstrated experimentally observed mass distribution, characterized by the peak-to-valley ratio, for wide range of initial compound-nucleus excitation energy up to 60MeV. The results show that, while neutron emission dominates at the ground state shape, it occurs along the shape evolution down to the scission point.
O
Prokhnenko, O.*; Nikitin, S. E.*; 金子 耕士; 田端 千紘; 廣瀬 雄介; 常盤 欣文; 芳賀 芳範; 藤田 全基; 野尻 浩之*; Anovitz, L. M.*; et al.
Physical Review B, 112(9), p.094402_1 - 094402_7, 2025/09
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)The spin dynamics in the natural mineral aegirine, NaFeSiO, a member of the pyroxene family, was studied using elastic and inelastic neutron scattering. Magnetization and specific heat measurements as well as single-crystal neutron diffraction maps confirm two successive magnetic transitions at 8.8 and 5.8~K, consistent with previous studies. The observed spin-wave excitations emerge from the incommensurate magnetic Bragg peaks corresponding to the propagation vector 
, and extend up to energies of about 1.5 meV. In the low-temperature helical phase, the spin dynamics of the Fe
ions is well described by a simple linear spin-wave model. The observed excitations can be modeled using a spin Hamiltonian that includes three primary exchange interactions. Our results show that no single exchange interaction dominates the spin dynamics. The similar strengths of the intrachain and interchain couplings point to the fact that the magnetic interactions in aegirine are three-dimensional, rather than being confined along one direction. As a result, the system cannot be considered quasi-one-dimensional, as previously suggested, and calls for further investigations.
/
for the 19.40-MeV state in 
Be for studying the 
Be(
,
)Li
reaction relevant to the cosmological lithium problem岩佐 直仁*; 西尾 勝久; 廣瀬 健太郎; 牧井 宏之; Orlandi, R.; 洲嵜 ふみ; Smallcombe, J.; 他7名*
Physical Review C, 112(3), p.035801_1 - 035801_6, 2025/09
被引用回数：2 パーセンタイル：70.29(Physics, Nuclear)The Li(
He,)Be()Li reaction was measured at 
(He) = 28 MeV for studying the Be(,)Li reaction, which is a Be destruction reaction in the big bang nucleosynthesis. Resonant states at 18.9
20.1 MeV in Be were populated by the Li(He,)Be reaction and decay protons to the ground (
) and first-excited states () in Li were well separated and measured. The resonance width 
and branching ratio / for the 19.40-MeV state in Be were deduced to be 342
112 keV and 11.2 3.5 5.0 (syst.)%, respectively. The 
Be(,)Li reaction cross section was deduced.
安部 諭; 廣瀬 意育; 柴本 泰照
Results in Engineering (Internet), 27, p.106307_1 - 106307_16, 2025/09
乱流ジェットの相互作用は、さまざまな工学的応用において熱および物質移動において重要な役割を果たす。特に、原子炉内におけるジェットの合流現象は、炉心出口温度(CET)を炉心加熱の指標として用いる際の信頼性を検証する上で重要である。CETは、事故時の対応方針の判断や原子炉の安全運転を確保するための主要な指標の一つである。これらのジェット相互作用の力学を理解することは、原子炉の安全性および運用効率の向上に不可欠である。さらに、シビアアクシデント時の格納容器内熱流動の分野では、格子状障害物とジェットの相互作用挙動が大きな関心を集めている。本研究では、格子状障害物の影響を受けるジェット流の流動特性をより深く理解するために、大渦シミュレーション(LES)を用いた。特に、乱流生成メカニズムに焦点を当てている。乱流モデルの精度向上のため、コヒーレント構造Smagorinskyモデル(CSM)を導入した。実験データとの比較により、LESがジェット流れの挙動解析に有用であることを確認した。ジェットの渦構造はQ-criterionを用いて可視化した。さらに、格子状障害物が乱流運動エネルギー生成率に及ぼす影響について、各位置における周方向プロファイルおよび累積生成量を通じて分析を行った。
高木 慎弥*; 有友 嘉浩*; 中島 滉太*; 岡田 和記; 廣瀬 健太郎; 西尾 勝久
Physical Review C, 112(1), p.014608_1 - 014608_7, 2025/07
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)Kinetic energy of individual fission fragment for actinide nuclei is, for example, important for evaluating the prompt-neutron spectrum in the laboratory system. It is experimentally known that kinetic energy for each fragment is constant at about 100 MeV for light fragments and that for heavy fragments decreases linearly with mass number. Most of the theoretical studies carried out so far attempted to calculate the total kinetic energy of both fragments, i.e. sum of the energies of two fragments, but the kinetic energy of each fragment was not analyzed in detail as far as we recognize. We have calculated them in thermal-neutron induced fission of 
Pu with a dynamical model using Langevin equations within a three-dimensional two-center parametrization. Also fission of 
Fm was investigated. It is calculated from the Coulomb energy at the scission point and the pre-scission kinetic energy. It is found that the pre-scission kinetic energy has about 2-4% contribution in the kinetic energy. The calculated results reproduce the trend of the experimental data.
神長 輝一*; 廣瀬 エリ; 他5名*
Journal of Radiation Research (Internet), 66(3), p.318 - 328, 2025/05
被引用回数：0 パーセンタイル：0.00(Biology)Due to the limited number of accelerator-based X-ray facilities worldwide that provide beams with an adjustable size, their application for radiobiological research purposes has been restricted. Thus, the development of alternative methods is of technical importance for investigating cell/tissue responses in spatially non-uniform radiation fields. In this study, we performed mini beam irradiation of cells using a lead (Pb) sub-milli-collimator as an alternative method to sub-millimeter beams. Also, we employed human cervical carcinoma HeLa cells and hTERT-immortalized fibroblast BJ-1 cells that express fluorescence ubiquitination-based cell-cycle indicators (FUCCI). Time-lapse imaging revealed differences in the behavior of HeLa and BJ-1 cells in spatially heterogeneous radiation fields; in the case of HeLa cells, G2/M phase-arrested cells in the cell population were clearly observed, distinguishing irradiated from non-irradiated cells at the sub-millimeter scale level. Our findings indicate that FUCCI can be useful as a biological dose indicator, depending on cell type, and Pb sub-milli-collimators show potential as a possible alternative to accelerator-based X-ray sub-millimeter beams for radiobiological research. The use of the collimators, unlike beamtime experiments in synchrotron facilities with the approval of the committee, is highly versatile and may be beneficial in preliminary studies in a normal laboratory environment.
Md produced in the 
He + 
Es reaction西尾 勝久; 廣瀬 健太郎; 牧井 宏之; Orlandi, R.; Kean, K. R.*; 塚田 和明; 豊嶋 厚史*; 浅井 雅人; 佐藤 哲也; Chiera, N. M.*; et al.
Physical Review C, 111(4), p.044609_1 - 044609_12, 2025/04
被引用回数：1 パーセンタイル：47.92(Physics, Nuclear)In spontaneous fission (SF) it is found that the mass-asymmetric fission of well-known actinides suddenly changes to the symmetric fission when nucleus has a mass number 
larger than 257. We have measured for the first time fission-fragment mass and total-kinetic-energy (TKE) distributions of the excited compound nucleus Md, populated in the reaction He+Es, using the rare isotope Es with a short half-life, 
=276 days. The fission of Md can be interpreted as involving 3 fission modes: an mass-asymmetric mode and two modes of mass-asymmetric fissions, the latter two are manifested by different TKE values. Predominantly symmetric fission was obtained at the excitation energy of 15.0 MeV. By increasing the energy to 18.0 MeV, the asymmetric fission mode dominates. Both such a strong change of fission modes within a small increase of excitation energy and the enhancement of asymmetric split are new phenomena in fission.
- telescope ERDA原山 勲; 廣瀬 靖*; 関場 大一郎*
Nuclear Instruments and Methods in Physics Research B, 554, p.165435_1 - 165435_6, 2024/09
被引用回数：0 パーセンタイル：0.00(Instruments & Instrumentation)-テレスコープERDA(Elastic Recoil Detection Analysis:反跳原子検出法)は、複数の軽元素を含む薄膜の組成分析に有効なイオンビーム表面分析手法である。複合アニオン化合物中の組成比O/Nの決定を目的とし、-テレスコープERDA装置を開発した。本装置では、反跳原子をガス電離箱で測定する。ガス電離箱では、通常用いられる平板形状の陰極ではなく、電極サイズを小さくしたU字形状の陰極を用いた。U字形状の陰極は、電離電子を陽極に収束して移動させる電場を形成するため、電極が小さくても電離電子を全量回収することができる。電極の小型化は、ガス電離箱自体のコンパクト化につながる。一方で、電離電子の収集効率や、ERDAの定量性など、陰極形状の違いによる影響については今まで検証されてこなかった。そこで本研究では、平板形状とU字形状の陰極でそれぞれ標準試料であるSrTiO
基板について、-テレスコープERDA測定を実施することで、陰極形状の違いによる影響の評価を行った。いずれの陰極形状においても、Oの信号強度は誤差範囲で一致しており、Oの定量結果は陰極形状によらず同じ結果を示すことが分かった。これは、ガス電離箱の電極形状が非平行平板であっても定量性を損なうことなく、また、ある程度電極形状は自由度を持つことを意味している。今後、非平行平板を用いることで、ビームラインへの設置が簡便な、よりコンパクトなガス電離箱の開発が期待される。
Sn wires with and without Cu-Nb reinforcement中本 美緒*; 菅野 未知央*; 荻津 透*; 杉本 昌弘*; 谷口 諒*; 廣瀬 清慈*; 川崎 卓郎; Gong, W.; Harjo, S.; 淡路 智*; et al.
IEEE Transactions on Applied Superconductivity, 34(5), p.8400806_1 - 8400806_6, 2024/08
被引用回数：1 パーセンタイル：10.70(Engineering, Electrical & Electronic)For an accelerator magnet, a certain mechanical strength is required to sustain against a transverse compression stress due to Lorentz force. A bronze-route NbSn wire with Cu-Nb reinforcement was developed by Tohoku University and Furukawa Electric to enhance the strength against axial tension. The Cu-Nb reinforcement wire also exhibited some indication of strength improvement against transverse compression; however, the details of a reinforcement mechanism for the transverse compression stress have not been clarified. In this study, the internal strains of NbSn bronze-route wires with and without the Cu-Nb reinforcement under transverse compression stress were evaluated by neutron diffraction at BL19 (TAKUMI) in J-PARC. The samples were attached to jig with solder only at the ends and compression was applied at the center of the samples with 30-mm anvil with 5-mm wide and 8- to 15-mm high beam. Since a critical current, Ic of a superconducting wire depends on the three-dimensional strain, internal strain of NbSn along the axial and two orthogonal radial directions were evaluated at room temperature (RT). In the different setup, Ic measurements of the wires under transverse compression stresses were also performed at 4.2 K and 14.5 T. Using 3-mm wide anvil, the transverse compression was applied at 4.2 K or RT. The neutron diffraction results indicated no significant differences in the internal strains of NbSn under transverse compression between the samples with and without Cu-Nb reinforcement, while the Ic measurements showed potential increase in the irreversible stress (
) for Cu-Nb reinforced wires. The reason for this discrepancy was discussed based on the difference in the experimental setups for each measurement.
和田 裕貴; 廣瀬 意育; 柴本 泰照
Ultrasonics, 141, p.107346_1 - 107346_16, 2024/07
被引用回数：6 パーセンタイル：64.67(Acoustics)Ultrasound tomography of bubbly two-phase flows using machine learning (ML) was investigated by performing two-dimensional ultrasound numerical simulations using a finite element method simulator. To date, studies on ultrasound tomography for two-phase flow measurements have been conducted only for some bubbles. However, in an actual bubbly flow, numerous bubbles are complexly distributed in the cross-section of the flow channel. This limitation of previous studies originates from the transmission characteristics of ultrasound waves through a medium. The transmission characteristics of ultrasound waves are different from those of other probe signals, such as radiation, electrical, and optical signals. In this study, the feasibility of combining ultrasound tomography with ML was evaluated for dense bubble distributions with up to 20 bubbles (cross-sectional average void fraction of approximately 0.29). We investigated the effects of the temporal length of the received waveform and number of sensors to optimize the system on the prediction performance of the bubble distribution. The simultaneous driving of the installed sensors was simulated to reduce the measurement time for the entire cross-section and verify the applicability of the method. Thus, it was confirmed that ultrasound tomography using ML has sufficient prediction performance, even for a complex bubble distribution with many bubbles, and that the cross-sectional average void fraction can be predicted with high accuracy.
廣瀬 エリ; 横谷 明徳*; 野口 実穂*; Huart, L.*; 鈴木 啓司*
放射線生物研究, 59(2), p.134 - 156, 2024/06
細胞が放射線照射を受けた後、どのようなプロセスをたどって長期期間を経て現れる発がんなどの放射線影響につながるのか、放射線の長期影響をゲノムの構造・機能変化とエネルギー代謝の2つの視点から論じる。放射線によるゲノムへの長期影響の一つとして、ゲノム不安定性が子孫細胞に受け継がれることがわかってきた。X線照射によりX染色体上のHPRT1遺伝子座に欠失を有するヒト細胞のクローン株を樹立し、これらを用いて筆者らが子孫細胞に受け継がれた大規模なDNA欠失を調べたところ、欠失部位の両端にはっきりとした境目がなく、少なくともX染色体上の約130-137 Mbにわたって、DNA欠失部分と残存部分がパッチワーク状に混在していることが分かった。これはX線照射時における細胞核内でのDNAの収納のされ方に依存して、放射線エネルギー付与の空間密度を反映したDSBの分布を示していると考えられる。また、一般に考えられている1Gyあたり約40個/細胞に生じるDSBの頻度を考慮すると、非DSB型クラスターDNA損傷の塩基除去修復によって引き起こされる 二次的なDSBに起因する欠失も生じたと考えられる。さらに、複雑なDNA欠失パターンがゲノム全体の機能に及ぼす影響を、遺伝子発現を指標に調べたところ、遺伝子発現変動は大規模欠失領域の近傍だけでなくDNA欠失が位置するX染色体全域に及んでいた。これは、二次的なDSBに伴うCTCF結合サイトの欠失が要因であることを示唆している。他方、放射線照射後に細胞周期から離脱し細胞周期を不可逆的に停止した細胞(放射線誘発早期老化細胞)の場合、放射線の長期影響がエネルギー代謝に現れる。放射線誘発早期老化細胞は、細胞周期が回転しないため、DNA合成や細胞分裂に必要なエネルギーは不要で、このため、正常細胞と比較してエネルギー代謝活性は、一見、低いと予想されがちである。しかし、ミトコンドリアの膜電位差を通じて代謝活性を調べたところ、放射線誘発早期老化細胞では、代謝活性が上昇する様子が観察され、代謝活性化に伴うATP量の増加も合わせて報告された。ミトコンドリア活性の亢進に伴い生産された活性酸素種が近傍の細胞の損傷を誘発すると考えられることから、放射線誘発早期老化細胞は長期にわたって周囲の正常細胞にも影響を与えることが予想される。本稿ではこのような、長い時間が経っても残り続ける放射線の"爪痕"について論じる。
Baccou, J.*; Glantz, T.*; Ghione, A.*; Sargentini, L.*; Fillion, P.*; Damblin, G.*; Sueur, R.*; Iooss, B.*; Fang, J.*; Liu, J.*; et al.
Nuclear Engineering and Design, 421, p.113035_1 - 113035_16, 2024/05
被引用回数：11 パーセンタイル：91.60(Nuclear Science & Technology)In the Best-Estimate Plus Uncertainty (BEPU) framework, the use of best-estimate code requires to go through a Verification, Validation and Uncertainty Quantification process (VVUQ). The relevance of the experimental data in relation to the physical phenomena of interest in the VVUQ process is crucial. Adequacy analysis of selected experimental databases addresses this problem. The outcomes of the analysis can be used to select a subset of relevant experimental data, to encourage designing new experiments or to drop some experiments from a database because of their substantial lack of adequacy. The development of a specific transparent and reproducible approach to analyze the relevance of experimental data for VVUQ still remains open and is the topic of this contribution. In this paper, the concept of adequacy initially introduced in the OECD/NEA SAPIUM (Systematic APproach for model Input Uncertainty quantification Methodology) activity is formalized. It is defined through two key properties, called representativeness and completeness, that allows considering the multifactorial dimension of the adequacy problem. A new systematic approach is then proposed to analyze the adequacy of a set of experimental databases. It relies on the introduction of two sets of criteria to characterize representativeness and completeness and on the use of multi-criteria decision analysis method to perform the analysis. Finally, the approach is applied in the framework of the new OECD/NEA ATRIUM activity which includes a set of practical IUQ exercises in thermal-hydraulics to test the SAPIUM guideline in determining input uncertainties and forward propagating them on an application case. It allows evaluating the adequacy of eight experimental databases coming from the Super Moby-dick, Sozzi-Sutherland and Marviken experiments and identifying the most adequate ones.
Sr in highly radioactive aqueous samples via conversion to a kinetically stable 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex followed by concentration-separation-fractionation based on capillary electrophoresis-liquid scintillation大内 和希; 原賀 智子; 廣瀬 和生*; 黒澤 結香*; 佐藤 義行; 渋川 雅美*; 齋藤 伸吾*
Analytica Chimica Acta, 1298, p.342399_1 - 342399_7, 2024/04
被引用回数：1 パーセンタイル：8.30(Chemistry, Analytical)従来の高線量試料分析法では被ばくリスクが高く、大量の二次放射性廃棄物が発生することから、放射線放出量を低減できる迅速な分析法が強く望まれている。このニーズに取り組むため、我々は液体シンチレーションカウンティングと2点検出によるキャピラリー過渡的等速電気泳動(ctITP)を組み合わせたSr定量法を開発した。これは、1,4,7,10-テトラアザシクロドデカン-1,4,7,10-テトラ酢酸(DOTA)-Sr錯体を1回の操作で分離・分画する方法である。高線量の放射性試料をマイクロリットルレベルで取り扱うことができ、従来のイオン交換法よりも大幅に高速であるこの方法により、実高線量廃棄物中のSrを選択的に定量した。ctITPにおける濃縮・分離の成功は、Sr-DOTA錯体が解離不活性であることに起因する。
U and 
ThFilipescu, D.*; Gheorghe, I.*; Goriely, S.*; 西尾 勝久; 宇都宮 弘章*; 洲嵜 ふみ; 廣瀬 健太郎; 他10名*
Physical Review C, 109(4), p.044602_1 - 044602_23, 2024/04
被引用回数：6 パーセンタイル：72.10(Physics, Nuclear)New measurements of photofission and photoneutron reactions on U and Th in the Giant Dipole Resonance (GDR) energy region have been performed at the laser Compton-scattering 
-ray source of the NewSUBARU synchrotron radiation facility. The photoneutron (
) with 
= 1-3 and photofission (
) reactions have been discriminated by considering a Gaussian distribution of prompt-fission-neutron (PFN) multiplicities predicted by the theory of evaporation in sequential neutron emission from excited fission fragments. We report experimental (
), (
), (
) and () cross sections, average energies of PFNs and of(, 
) photoneutrons, as well as the mean number of PFNs per fission and the width of the PFNs multiplicity distribution. Based on these primary experimental results and combined with reasonable assumptions, we extract also the first- and second-chance fission contributions.
廣瀬 意育; 安部 諭; 石垣 将宏*; 柴本 泰照; 日引 俊*
Progress in Nuclear Energy, 169, p.105085_1 - 105085_13, 2024/04
被引用回数：1 パーセンタイル：19.36(Nuclear Science & Technology)Immersed boundary methods (IBMs) have been developed as complementary methods for computational fluid dynamics (CFD). They allow a flow simulation in a mock-up model that includes complex-shaped inner structures and/or boundaries with a non-body conformal mesh. Such a model might force us to create a complicated body-fitted mesh with a high cost in the conventional CFD (CCFD) approach. We focus on the Brinkman penalization (BP) method and its extended version, which we call here the extended Brinkman penalization method (EBP), among the different types of IBMs, aiming to apply them to the phenomena that occur during severe accidents in a nuclear reactor containment vessel and explore the possibility that the methods can partially replace the CCFD. In this paper, as a preliminary step to validate the applicability of these methods, we measure the jet flow rectified by a grating-type structure used for the validation of numerical techniques and apply them to simulate the behavior of an upward jet rectified by a horizontally placed grating-type structure modeled as an immersed body. This type of structure is generally used in reactor buildings, and it is crucial to evaluate their influence on gaseous flows because the behaviors of hydrogen produced during severe accidents may be influenced by them. The structure is selected as our subject because it has moderate complexity, enabling us to examine the effects of the IBMs and compare them with CCFD. We investigate whether these methods can reproduce a result of corresponding CCFD in which the grating is modeled as body-conformal mesh and show that the former can produce the latter with equivalent accuracy. All these results are also compared with the experimental data on the flow velocity distributions downstream of the grating measured using particle image velocimetry.
