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論文

Parity assignment for low-lying dipole states in $$^{58}$$Ni

静間 俊行*; Omer, M.; 早川 岳人*; 湊 太志*; 松葉 俊哉*; 宮本 修治*; 清水 則孝*; 宇都野 穣

Physical Review C, 109(1), p.014302_1 - 014302_7, 2024/01

 被引用回数:0 パーセンタイル:0.19(Physics, Nuclear)

Low-lying dipole states in the singly closed-shell nucleus $$^{58}$$Ni were studied via nuclear resonance fluorescence experiments using a quasi-monoenergetic, linearly polarized photon beam. The parity quantum numbers of the dipole states were determined by the intensity asymmetry of resonantly scattered $$gamma$$-rays with respect to the polarization plane of the incident photon beam. The electric and magnetic dipole (E1 and M1) strengths at excitation energies between 5.9 and 9.8 MeV were obtained based on dipole strengths taken from literature. The E1 and M1 strength distributions were compared with large-scale shell-model predictions in the $$fp$$-shell using the SDPFSDG-MU interaction.

論文

General-purpose nuclear data library JENDL-5 and to the next

岩本 修; 岩本 信之; 国枝 賢; 湊 太志; 中山 梓介; 木村 敦; 中村 詔司; 遠藤 駿典; 長家 康展; 多田 健一; et al.

EPJ Web of Conferences, 284, p.14001_1 - 14001_7, 2023/05

 被引用回数:0 パーセンタイル:0.21(Nuclear Science & Technology)

Japanese Evaluated Nuclear Data Library version 5 (JENDL-5) was released in 2021. JENDL-5 is intended to extend its generality from JENDL-4.0 by covering a wide variety of nuclear data for applications not only to nuclear design and decommissioning, but also to radiation-related fields. Overview of JENDL-5 and a future plan for the next of JENDL-5 are presented. JENDL-5 includes up-to-date neutron reaction cross sections incorporating other various types of data such as newly evaluated nuclear decay, fission yield, and thermal neutron scattering law. The neutron induced reaction cross sections especially on minor actinides in the resonance regions are improved by the experimental data measured at ANNRI. The extensive benchmark analyses on neutron nuclear data were made and the performance of JENDL-5 was confirmed by benchmark tests of ICSBEP and IRPhEP as well as fast reactors, radiation shielding calculations, and so on. So far, several JENDL special-purpose files have been developed for various applications. The data cover neutron, charged particles, and photon induced reactions. As the neutron induced reaction files, two special purpose files of JENDL/AD-2017 and JENDL/ImPACT-2018 were released to meet needs of nuclear backend applications including activation evaluation for nuclear facilities and nuclear transmutations of high-level radioactive wastes of long-lived fission products, respectively. Furthermore, the photon, proton and deuteron data were released as JENDL/PD-2016.1, JENDL-4.0/HE and JENDL/DEU-2020, respectively, for accelerator applications. With updating the data, they were incorporated in JENDL-5 as sub-libraries for facilitation of usability of JENDL. As the next step of JENDL-5, provision of the proper and sufficient covariance will be a major challenge, where cross correlations across different reactions or data-types may play a significant role in connection with data assimilation for various applications.

論文

Nuclear many-body effects on particle emission following muon capture on $$^{28}$$Si and $$^{40}$$Ca

湊 太志; 内藤 智也*; 岩本 修

Physical Review C, 107(5), p.054314_1 - 054314_10, 2023/05

 被引用回数:1 パーセンタイル:64.66(Physics, Nuclear)

Muon captures on nuclei have provided us a plenty of knowledge of nuclear properties. Recently, this nature attracts attention again in electronics, because it is argued that charged particle emissions following muon capture on silicon triggers non-negligible soft errors in semiconductors. To investigate the particle emissions from nuclear physics point of view, we develop a new approach using a microscopic model of muon capture and an up-to-date particle emission models. We paid attention to the muon capture rates, the particle emission spectra, and the multiplicities that have a close interrelation with each other, and found that the nuclear many-body correlation including two-particle two-hole excitations is a key to explain them simultaneously.

論文

High-sensitive XANES analysis at Ce L$$_{2}$$-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samples

Li, W.*; 山田 真也*; 橋本 直; 奥村 拓馬*; 早川 亮大*; 新田 清文*; 関澤 央輝*; 菅 大暉*; 宇留賀 朋哉*; 一戸 悠人*; et al.

Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02

 被引用回数:4 パーセンタイル:29.37(Chemistry, Analytical)

希土類元素は放射性元素であるアクチノイドのアナログ元素としてしばしば利用される。セリウム(Ce)は希土類元素の中でも+3価と+4価の両方をとり得る特別な元素である。環境試料中のCeの+3価と+4価の比を調べる手段としてX線吸収端近傍構造(XANES)が有力であったが、チタン濃度が高いと蛍光X線の干渉のために測定ができないという問題があった。本研究では、L$$_{3}$$吸収端だけでなくL$$_{2}$$吸収端を調べ、さらに新しい検出器であるtransition-edge sensor (TES)を利用することでこれまでは測定が難しかった試料も測定可能にした。この結果は様々な環境試料に応用可能である。

論文

Japanese Evaluated Nuclear Data Library version 5; JENDL-5

岩本 修; 岩本 信之; 国枝 賢; 湊 太志; 中山 梓介; 安部 豊*; 椿原 康介*; 奥村 森*; 石塚 知香子*; 吉田 正*; et al.

Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01

 被引用回数:75 パーセンタイル:99.99(Nuclear Science & Technology)

The fifth version of Japanese Evaluated Nuclear Data Library, JENDL-5, was developed. JENDL-5 aimed to meet a variety of needs not only from nuclear reactors but also from other applications such as accelerators. Most of the JENDL special purpose files published so far were integrated into JENDL-5 with revisions. JENDL-5 consists of 11 sublibraries: (1) Neutron, (2) Thermal scattering law, (3) Fission product yield, (4) Decay data, (5) Proton, (6) Deuteron, (7) Alpha-particle, (8) Photonuclear, (9) Photo-atomic, (10) Electro-atomic, and (11) Atomic relaxation. The neutron reaction data for a large number of nuclei in JENDL-4.0 were updated ranging from light to heavy ones, including major and minor actinides which affect nuclear reactor calculations. In addition, the number of nuclei of neutron reaction data stored in JENDL-5 was largely increased; the neutron data covered not only all of naturally existing nuclei but also their neighbor ones with half-lives longer than 1 day. JENDL-5 included the originally evaluated data of thermal scattering law and fission product yield for the first time. Light charged-particle and photon induced reaction data were also included for the first time as the JENDL general purpose file.

論文

The Optical potential for neutron-nucleus scattering derived by Bayesian optimization

渡辺 証斗*; 湊 太志; 木村 真明*; 岩本 信之

JAEA-Conf 2022-001, p.103 - 108, 2022/11

We are working on a combination of nuclear reaction calculation code CCONE and machine learning libraries to generate nuclear data and improve their accuracy. The angular distributions of elastic and inelastic scatterings to the first excited state on $$^{54}$$Fe at several incident energies were calculated using CCONE, and the optical potential parameters were optimized to reproduce the experimental data by Bayesian optimization. The optimized parameters were the depth of the real volume and imaginary surface parts of the potential, their energy dependence, radius, and diffuseness. Using the obtained optical potential, we estimated the angular distributions at energies different from those used on the optimization, and found that the results were in good agreement with the experiment data. In this presentation, we will introduce these calculation results and future prospects.

論文

Nuclear data generation by machine learning, 1; Application to angular distributions for nucleon-nucleus scattering

渡辺 証斗*; 湊 太志; 木村 真明*; 岩本 信之

Journal of Nuclear Science and Technology, 59(11), p.1399 - 1406, 2022/11

 被引用回数:0 パーセンタイル:0.01(Nuclear Science & Technology)

In order to increase the efficiency of nuclear data evaluation, we have tested a combination of a nuclear reaction model and machine learning algorithm. We calculated nucleon-nucleus elastic scattering angular distributions by using the nuclear reaction model code, and optimized the potential parameters of an optical model to reproduce experimental data by means of the Bayesian optimization. We present optimization cases with the single parameter and two or more parameters, and show that our framework gives the angular distributions which are in good agreement with the observed ones.

論文

Reduction and resource recycling of high-level liquid radioactive waste through nuclear transmutation, 4; ImPACT/LLFP-2018: A New nuclear data library for a challenge on transmutation of long-lived fission products

国枝 賢; 古立 直也*; 湊 太志; 岩本 信之; 岩本 修

NEA/NSC/R(2020)4 (Internet), p.329 - 331, 2022/10

長寿命核分裂生成核種の核変換研究のために、新たな核データライブラリImPACT/LLFP-2018を開発した。測定データの少ない不安定核種の核反応断面積を推定するために、微視的理論に基づく核構造モデルをCCONEコードに導入した。また、理化学研究所で得られた最新の断面積測定データを用いて高エネルギー反応で重要な前平衡パラメータを決定した。開発したライブラリには$$^{79}$$Se, $$^{93}$$Zr, $$^{107}$$Pdおよび$$^{135}$$Csを含む160核種に対する中性子および陽子入射の断面積が200MeVをエネルギー上限に格納されている。さらに、既存の安定核種に対する測定値と比較することにより調査した結果、本ライブラリは他のライブラリと比べて実験データへの再現性が高いことが判った。

論文

Anisotropic superconducting spin transport at magnetic interfaces

大湊 友也*; 山影 相*; 松尾 衛

Physical Review B, 106(16), p.L161406_1 - L161406_6, 2022/10

 被引用回数:9 パーセンタイル:75.56(Materials Science, Multidisciplinary)

We present a theoretical investigation of anisotropic superconducting spin transport at a magnetic interface between a $$p$$-wave superconductor and a ferromagnetic insulator. Our formulation describes the ferromagnetic resonance modulations due to spin current generation depending on spin-triplet Cooper pair, including the frequency shift and enhanced Gilbert damping, in a unified manner. We find that the Cooper pair symmetry is detectable from the qualitative behavior of the ferromagnetic resonance modulation. Our theory paves the way toward anisotropic superconducting spintronics.

論文

Calculation of $$beta$$-decay half-lives within a Skyrme-Hartree-Fock-Bogoliubov energy density functional with the proton-neutron quasiparticle random-phase approximation and isoscalar pairing strengths optimized by a Bayesian method

湊 太志; Niu, Z.*; Liang, H.*

Physical Review C, 106(2), p.024306_1 - 024306_13, 2022/08

 被引用回数:6 パーセンタイル:80.72(Physics, Nuclear)

For radioactive nuclear data, $$beta$$ decay is one of the important information and is applied to various fields. However, some of the $$beta$$-decay data is not available due to experimental difficulties. From this respect, theoretically calculated results have been embedded in the $$beta$$-decay data to compensate the missing information. To calculate the $$beta$$-decay half-lives, a proton-neutron quasi-particle random phase approximation on top of a Skryme energy density functional is applied in this work. The isoscalar pairing strength that is sensitive to half-lives is estimated by a Bayesian neutral network (BNN). We found that the half-lives calculated with the BNN isoscalar pairing strengths could reproduce most of experimental data. We also studied that the predictive performance on new experimental data that are not used for the BNN training and found that they are reproduced well.

論文

Ferromagnetic resonance modulation in $$d$$-wave superconductor/ferromagnetic insulator bilayer systems

大湊 友也*; 山影 相*; 加藤 岳生*; 松尾 衛

Physical Review B, 105(20), p.205406_1 - 205406_7, 2022/05

 被引用回数:9 パーセンタイル:79.16(Materials Science, Multidisciplinary)

We investigate ferromagnetic resonance (FMR) modulation in $$d$$-wave superconductor (SC)/ferromagnetic insulator (FI) bilayer systems theoretically. The modulation of the Gilbert damping in these systems reflects the existence of nodes in the $$d$$-wave SC and shows power-law decay characteristics within the low-temperature and low-frequency limit. Our results indicate the effectiveness of the use of spin pumping as a probe technique to determine the symmetry of unconventional SCs with high sensitivity for nanoscale thin films.

論文

Valley transport driven by dynamic lattice distortion

大湊 友也*; 大上 能悟*; 松尾 衛

Physical Review B, 105(19), p.195409_1 - 195409_9, 2022/05

 被引用回数:1 パーセンタイル:15.88(Materials Science, Multidisciplinary)

Angular momentum conversion between mechanical rotation and the valley degree of freedom in 2D Dirac materials is investigated theoretically. Coupling between the valley and vorticity of dynamic lattice distortions is derived by applying the $$kcdot p$$ method to 2D Dirac materials with an inertial effect. Lattice strain effects are also incorporated. Valley transfer and valley-dependent carrier localization are predicted using the dynamic lattice distortions. The transport properties are found to be controllable, allowing the system to be insulating and to generate pulsed charge current. Our formalism offers a route toward mechanical manipulation of valley dynamics in 2D Dirac materials.

論文

Estimated isotopic compositions of Yb in enriched $$^{176}$$Yb for producing $$^{177}$$Lu with high radionuclide purity by $$^{176}$$Yb($$d,x$$)$$^{177}$$Lu

永井 泰樹*; 川端 方子*; 橋本 慎太郎; 塚田 和明; 橋本 和幸*; 本石 章司*; 佐伯 秀也*; 本村 新*; 湊 太志; 伊藤 正俊*

Journal of the Physical Society of Japan, 91(4), p.044201_1 - 044201_10, 2022/04

 被引用回数:2 パーセンタイル:44.06(Physics, Multidisciplinary)

近年、神経内分泌腫瘍を治療するための医療用RIとして$$^{177}$$Luが注目されており、加速器施設で重陽子を濃縮$$^{176}$$Yb試料に照射し、高純度の$$^{177}$$Luを製造する方法が検討されている。ただし、Yb試料には様々な同位体が微量に含まれており、$$^{177}$$Lu以外のLu同位体が不純物として生成される。医療用として利用する$$^{177}$$Luは一定の純度が求められるため、定量的にLuの不純物を評価する手法が求められていた。本研究では、実験値を基に関与する全てのYb($$d,x$$)Lu反応の断面積を決定し、粒子輸送計算コードPHITSと組み合わせることで、Yb試料が任意の組成比をもつ場合の各Lu同位体の生成量を推定する新しい手法を開発した。他に、天然組成のYb試料へ25MeV重陽子を照射した実験も行い、本手法の有効性を検証した。また、市販の濃縮$$^{176}$$Yb試料に照射した条件で計算を行い、重陽子のエネルギーを15MeVとすることで、純度99%以上の$$^{177}$$Lu生成を達成できることを示した。開発した手法は、加速器を用いて高純度の医療用$$^{177}$$Luを製造する際、必要な濃縮Yb試料の同位体組成を議論する上で重要な役割を果たすものである。

論文

$$beta$$-delayed neutron-emission and fission calculations within relativistic quasiparticle random-phase approximation and a statistical model

湊 太志; Marketin, T.*; Paar, N.*

Physical Review C, 104(4), p.044321_1 - 044321_18, 2021/10

AA2020-0834.pdf:4.84MB

 被引用回数:23 パーセンタイル:96.12(Physics, Nuclear)

$$r$$-processに対する$$beta$$遅発中性子および遅発核分裂の影響は大きな関心を集めている。近年、遅発中性子と遅発核分裂に関する研究報告数は増えてきているが、$$r$$-processシミュレーションにおける遅発中性子と遅発核分裂の不定性は、依然として大きい。このような背景のもと、信頼性のある遅発中性子と遅発核分裂の新しいデータテーブルの作成が望まれている。本研究では、従来モデルよりも遅発中性子と遅発核分裂を精確に計算することができる新しい理論的な枠組みを開発し、それを新しいデータテーブル作成に応用した。計算された遅発中性子の分岐率において、実験値との平均二乗誤差を計算すると、先行の研究報告と同等以上の結果を得ることができた。また、中性子過剰核になるほど遅発中性子放出に伴う先行核からのエネルギーの引き出しが、遅発中性子の分岐比に大きな影響を与えていることが分かった。遅発核分裂の分岐比は、使用する核分裂バリアデータによって、大きく依存することも分かった。今回作られた新しいデータテーブルは、今後$$r$$-process研究や原子力分野に応用することが期待される。

論文

Development of a reference database for beta-delayed neutron emission

Dimitriou, P.*; Dillmann, I.*; Singh, B.*; Piksaikin, V.*; Rykaczewski, K. P.*; Tain, J. L.*; Algora, A.*; Banerjee, K.*; Borzov, I. N.*; Cano-Ott, D.*; et al.

Nuclear Data Sheets, 173, p.144 - 238, 2021/03

 被引用回数:23 パーセンタイル:96.46(Physics, Nuclear)

核分裂の発見以降、核分裂片から放出される遅発中性子の存在には、数多くの関心が集められてきた。原子力発電では、遅発中性子は原子炉動特性の計算や炉の安全運転において非常に重要な役割を演じている。それに加え、遅発中性子は、核構造や天体核、特に新世代のRIビーム施設の中心課題である安定線から離れた原子核でも、大きなインパクトをもっている。現在、ベータ崩壊半減期と遅発中性子分岐比に関するいくつかの文献が利用可能であるが、測定と評価によって実施されるべき十分な考証は、それらの文献ではしばしば抜けている。この欠落部に注目し、遅発中性子の核データ評価とそれに関する新しい文献作成の作業が、国際原子力機関(IAEA)の援助の基に着手され、「ベータ遅発中性子用データベースの開発」に関するCoordinated Research Project (CRP)が結成された。本論文では、CRPで行われたこれまでの結果について報告をする。

論文

Reactions of the Li$$_{2}$$MnO$$_{3}$$ cathode in an all-solid-state thin-film battery during cycling

引間 和浩*; 日沼 洋陽*; 清水 啓佑*; 鈴木 耕太*; 田港 聡*; 平山 雅章*; 増田 卓也*; 田村 和久; 菅野 了次*

ACS Applied Materials & Interfaces, 13(6), p.7650 - 7663, 2021/02

 被引用回数:12 パーセンタイル:66.55(Nanoscience & Nanotechnology)

(001)配向したLi$$_{2}$$MnO$$_{3}$$薄膜を正極とした全固体リチウムイオン電池を作成し、表面X線回折法で表面構造を解析した。LiPO$$_{4}$$をコーティングした電極は、徐々に活性化し、活性化が終わると電池容量は維持されることがわかった。LiPO$$_{4}$$をコーティングした正極では、表面におけるMnやOの組成の変化がないためであると結論した。すなわち、本系は充放電に対して安定である特長を有することが判明した。このことはまた、今後の実用化に向け、重要な知見を与える結果である。

論文

Evaluation of fission product yields and associated covariance matrices

椿原 康介*; 奥村 森*; 石塚 知香子*; 吉田 正*; 湊 太志; 千葉 敏*

Journal of Nuclear Science and Technology, 58(2), p.151 - 165, 2021/02

AA2020-0468.pdf:2.37MB

 被引用回数:10 パーセンタイル:78.21(Nuclear Science & Technology)

The independent and cumulative fission product yields (FPYs) and their covariance matrices were newly evaluated for thermal- and fast-neutron induced fission and spontaneous fission. We principally evaluated the independent isobaric charge distributions by taking account of available experimental data, especially putting emphasis on the shell and even-odd staggering in the fission yields by applying a Boltzmann factor including the shell and the pairing correction energies for the mass of fission products. Furthermore, the isomeric ratios of FPY were obtained by a systematic calculation based on the Hauser-Feshbach theory. Normalization of the FPY and associated covariance matrices of independent FPY were determined based on the generalised least-square method to make them consistent with important physical constraints. Especially, the FPYs were normalized to be consistent with the mass chain yield of England and Rider. The cumulative FPYs were calculated by following the relevant $$beta$$-decay chain by using the decay data from JENDL/DDF-2015. Finally, we verified the FPYs evaluated presently by considering experimental decay heats, delayed neutron yields, aggregate antineutrino spectra and results from post-irradiation examination. All the results have shown that the present set of FPYs were consistent with these data, and free from trivial problems present in JENDL/FPY-2011.

論文

Low-lying electric and magnetic dipole strengths in $$^{207}$$Pb

静間 俊行*; 湊 太志; Omer, M.*; 早川 岳人*; 大垣 英明*; 宮本 修治*

Physical Review C, 103(2), p.024309_1 - 024309_8, 2021/02

AA2020-0675.pdf:0.29MB

 被引用回数:4 パーセンタイル:55.56(Physics, Nuclear)

$$^{207}$$Pbの低エネルギー双極子強度を準モノクロ=線形偏極フォトンビームの光核散乱を使って調べ、6.8MeVまでの励起エネルギーにおける電磁双極子($$E1$$)および磁気双極子強度($$M1$$)を導出した。今回の($$vec{gamma}$$,$$gamma'$$)反応の結果は、過去に行われた($$gamma$$,$$n$$)反応のデータと合わせて、中性子閾値近傍のエネルギーにおける$$E1$$$$M1$$の光吸収反応断面積を求めるために使った。得られた測定結果は、乱雑位相近似法+粒子振動カップリング法による理論計算の結果と比較し、核構造の観点から議論を行う。

論文

Experimental study of the $$Gamma_{p1}/Gamma_{p0}$$ ratios of resonance states in $$^{8}$$Be for deducing the $$^{7}$$Be($$n$$,$$p_{1}$$)$$^{7}$$Li$$^{*}$$ reaction rate relevant to the cosmological lithium problem

岩佐 直仁*; 石川 竣喜*; 久保野 茂*; 榊原 昂浩*; 小湊 和也*; 西尾 勝久; 松田 誠; 廣瀬 健太郎; 牧井 宏之; Orlandi, R.; et al.

Physical Review C, 103(1), p.015801_1 - 015801_5, 2021/01

 被引用回数:1 パーセンタイル:18.12(Physics, Nuclear)

The $$^{9}$$Be($$^{3}$$He,$$alpha$$)$$^{8}$$Be($$p$$)$$^{7}$$Li reaction was studied at $$E_{rm lab}$$($$^{3}$$He)=30 MeV to deduce the branching ratios of $$Gamma_{p1}/Gamma_{p0}$$ of resonant state at 18.91 - 20.1 MeV in $$^{8}$$Be, which are necessary to extract the $$^{7}$$Be($$n$$, $$p_{1}$$)$$^{7}$$Li$$^{*}$$ reaction rate relevant to the $$^{7}$$Be destruction in the big bang nucleosynthesis, from the $$^{7}$$Li($$p$$,$$n_{0}$$)$$^{7}$$Be reaction cross section. The decay protons from $$^{8}$$Be$$^{*}$$ to the ground and first excited states in $$^{7}$$Li were well-separately measured. The $$Gamma_{p1}/Gamma_{p0}$$ ratio of the 19.235-MeV state was deduced to be 3.4$$pm$$1.9%. The 19.86- and 20.1-MeV states were found to decay dominantly into the first excited and ground states of $$^{7}$$Li, respectively.

論文

原子力機構(JAEA)核図表アンケート集計

湊 太志; 小浦 寛之

核データニュース(インターネット), (127), p.46 - 62, 2020/10

核データ研究グループが発行しているJAEA核図表では、2018年度版の発行の際に利用希望者にアンケートの回答をお願いさせていただいた。本報告では、アンケートの集計結果について報告を行う。また、核図表の有償化についての結論と今後の方向性について現状を報告する。

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