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Reiser, J. T.*; Neeway, J. J.*; Cooley, S. K.*; Parruzot, B.*; Heredia-Langner, A.*; Gin, S.*; Thomas, M.*; Smith, N. J.*; Icenhower, J. P.*; Stone-Weiss, N.*; et al.
International Journal of Applied Glass Science, 16(4), p.e16707_1 - e16707_16, 2025/10
被引用回数:0 パーセンタイル:0.00(Materials Science, Ceramics)A new technique, termed the stirred-reactor coupon analysis (SRCA) method, has been developed to measure the rate of glass dissolution in forward-rate conditions. Monolithic glass coupons are partially masked with an inert material before placement in a large volume of well-mixed solution with known chemistry and temperature for a predetermined duration. After the test, the mask is removed, and the difference in step height between the protected area and the exposed corroded portions of the sample coupon is measured to determine the extent of glass dissolution. The step height is converted to a rate measurement using the test duration and glass density. Test parameters such as sample surface preparation and test duration were evaluated to determine their effects on the measured rates. Additionally, results from an interlaboratory study (ILS) consisting of 12 laboratories from 11 different institutions are presented, where each laboratory performed 12 independent tests. When removing experimental outlier data, the 95% reproducibility limits for the SRCA method has no statistical difference with previously published standardized test methods used to determine the forward rate of glass dissolution. Overall, this paper describes steps necessary to perform the test method and provides the statistical calculations to evaluate test accuracy.
藤澤 唯太*; Krishnadas, A*; 中村 友謙*; Hsu, C.-H.*; Smith, B.*; Pardo-Almanza, M*; 比屋根 芳周*; Chang, G.*; 永井 佑紀; 町田 理*; et al.
Physical Review B, 110(22), p.224511_1 - 224511_5, 2024/12
被引用回数:2 パーセンタイル:14.28(Materials Science, Multidisciplinary)エキゾチックな超伝導体の超伝導磁束の振る舞いを明らかにすることは、今後のデバイス開発にとって重要である。超伝導体LiTi
O
(111)の薄膜を作製し、磁場中での電子状態を走査型トンネル顕微鏡によって観測した。その際、接合部分の曲率に応じて超伝導磁束の状態が大きく変化することがわかった。そして、その変化は理論計算によっても確かめられた。この結果は、Josephson磁束を実験的な構造変化によってコントロールできる可能性を示唆しており、今後の新たなデバイス開発において重要な結果となるだろう。
-
hybridization intertwined with anomalous ground state formation in the van der Waals itinerant magnet Fe
GeTe
山神 光平*; 藤澤 唯太*; Pardo-Almanza, M*; Smith, B. R. M.*; 角田 一樹; 竹田 幸治; 岡田 佳憲*
Physical Review B, 106(4), p.045137_1 - 045137_8, 2022/07
被引用回数:10 パーセンタイル:54.38(Materials Science, Multidisciplinary)Fe
GeTe
is a van der Waals (vdW) coupled unconventional ferromagnetic metal with a high Curie temperature (
), exceeding 300 K. The formation of an anomalous ground state far below
has attracted great interest, leading to a need to understand the spin-polarized electronic state near the Fermi energy (
) at low temperature. Despite recent extensive study, a microscopic understanding of the spin polarized electronic structure around
has not been established yet due to the intrinsic complexity of both the crystal and band structures. In this work, we investigate the temperature dependence of element-specific soft X-ray magnetic circular dichroism (XMCD). Systematic temperature evolution in the XMCD signal from both magnetic Fe and its ligand Te is clearly observed. Importantly, the enhancement of the hybridization between Fe 3
and Te 5
states in the zero-magnetic field limit has been revealed. In light of the possible emergence of an exotic ground state, we discuss the temperature and magnetic field evolution of the element specific XMCD results.
Martin, P. G.*; Jones, C. P.*; Bartlett, S.*; Ignatyev, K.*; Megson-Smith, D.*; 佐藤 志彦; Cipiccia, S.*; Batey, D. J.*; Rau, C.*; 末木 啓介*; et al.
Scientific Reports (Internet), 10, p.22056_1 - 22056_17, 2020/12
被引用回数:4 パーセンタイル:18.53(Multidisciplinary Sciences)The structural form and elemental distribution of material originating from different Fukushima Daiichi Nuclear Power Plant reactors (Units 1 and 3) is hereby examined to elucidate their contrasting release dynamics and the current in-reactor conditions to influence future decommissioning challenges. Complimentary computed X-ray absorption tomography and X-ray fluorescence data show that the two suites of Si-based material sourced from the different reactor Units have contrasting internal structure and compositional distribution. The known event and condition chronology correlate with the observed internal and external structures of the particulates examined, which suggest that Unit 1 ejecta material sustained a greater degree of melting than that likely derived from reactor Unit 3. In particular, we attribute the near-spherical shape of Unit 1 ejecta and their internal voids to there being sufficient time for surface tension to round these objects before the hot (and so relatively low viscosity) silicate melt cooled to form glass. In contrast, a more complex internal form associated with the sub-mm particulates invoked to originate from Unit 3 suggest a lower peak temperature, over a longer duration. Using volcanic analogues, we consider the structural form of this material and how it relates to its environmental particulate stability and the bulk removal of residual materials from the damaged reactors. We conclude that the brittle and angular Unit 3 particulate are more susceptible to further fragmentation and particulate generation hazard than the round, higher-strength, more homogenous Unit 1 material.
Dimitriou, P.*; Basunia, S*; Bernstein, L.*; Chen, J.*; Elekes, Z.*; Huang, X.*; Hurst, A.*; 飯村 秀紀; Jain, A. K.*; Kelley, J.*; et al.
EPJ Web of Conferences, 239, p.15004_1 - 15004_4, 2020/09
被引用回数:0 パーセンタイル:0.00(Nuclear Science & Technology)評価済み核構造データファイル(Evaluated Nuclear Structure Data File: ENSDF)は、原子核構造と崩壊に関する様々な実験データを全ての核種について集めて、それらの実験データの評価値を与えてある世界唯一のデータファイルである。ENSDFは定期的に更新されており、そのための評価作業は各国の評価者で分担している。評価作業を速やかに行うために、IAEAの援助の下に評価者の国際的なネットワークが組織されている。この発表では、ネットワークの最近の活動のうち、ENSDFの処理コードの開発、測定が必要とされているデータのリストの作成、インターネット版核図表の利用の拡充などについて報告する。また、核構造・崩壊データの需要が増大しているにもかかわらず、評価者が減っている問題についても述べる。
-decay branching ratio of
PtCubiss, J. G.*; Harding, R. D.*; Andreyev, A. N.; Althubiti, N.*; Andel, B.*; Antalic, S.*; Barzakh, A. E.*; Cocolios, T. E.*; Day Goodacre, T.*; Farooq-Smith, G. J.*; et al.
Physical Review C, 101(1), p.014314_1 - 014314_4, 2020/01
被引用回数:5 パーセンタイル:40.20(Physics, Nuclear)
Ptの基底状態から娘核
Osの基底状態への
崩壊分岐比を0.52(5)%と、過去の値と比較してより高精度で再決定した。
PtはCERN-ISOLDE実験施設において
Hgを単離し、その
崩壊孫核種として生成した。今回の結果を用いて導出した
崩壊の換算崩壊幅は、中性子欠損Pt同位体の
崩壊幅の系統性について新しい描像を与えることとなった。
Hg,
Hg,
Hg and
HgWrzosek-Lipska, K.*; Rezynkina, K.*; Bree, N.*; Zieli
ska, M.*; Gaffney, L. P.*; Petts, A.*; Andreyev, A. N.; Bastin, B.*; Bender, M.*; Blazhev, A.*; et al.
European Physical Journal A, 55(8), p.130_1 - 130_23, 2019/08
被引用回数:18 パーセンタイル:79.63(Physics, Nuclear)The neutron-deficient mercury isotopes serve as a classical example of shape coexistence, whereby at low energy near-degenerate nuclear states characterized by different shapes appear. The electromagnetic structure of even-mass
Hg isotopes was studied using safe-energy Coulomb excitation of neutron-deficient mercury beams delivered by the REX-ISOLDE facility at CERN. The population of 0
, 2
, and 4
states was observed in all nuclei under study. Reduced
matrix elements coupling populated yrast and non-yrast states were extracted, including their relative signs. These are a sensitive probe of shape coexistence and may be used to validate nuclear models. The experimental results are discussed in terms of mixing of two different configurations and are compared with three different model calculations: the Beyond Mean Field model, the Interacting Boson Model with configuration mixing and the General Bohr Hamiltonian. Partial agreement with experiment was observed, hinting to missing ingredients in the theoretical descriptions.
Sn and spin-orbit splitting in neutron-rich nucleiOrlandi, R.; Pain, S. D.*; Ahn, S.*; Jungclaus, A.*; Schmitt, K. T.*; Bardayan, D. W.*; Catford, W. N.*; Chapman, R.*; Chipps, K. A.*; Cizewski, J. A.*; et al.
Physics Letters B, 785, p.615 - 620, 2018/10
被引用回数:11 パーセンタイル:60.07(Astronomy & Astrophysics)Low-lying neutron-hole states in
Sn were populated via the
Sn(d,t) reaction at Oak Ridge National Laboratory. The triton angular distributions were compared to DWBA calculations and revealed spectroscopic factors compatible with a single-hole nature of the states populated. The data permit to determine the spin-orbit splitting of the strongly bound
and
neutron orbits below the shell gap, which was compared to the splitting of the weakly bound 3
and 2
orbits above the gap. The comparison revealed a smaller energy splitting of the 3
orbits. All splittings were reproduced using Woods-Saxon calculations, and the lower splitting of the 3
orbits was explained to arise from the large radial extent of the wavefunction and small value of the amplitude at the surface. This result is important to understand at a fundamental level the spin-orbit interaction, and its effects on neutron-rich nuclei.
-spectroscopy at an intense cold neutron beam facilityJentschel, M.*; Blanc, A.*; de France, G.*; K
ster, U.*; Leoni, S.*; Mutti, P.*; Simpson, G.*; Soldner, T.*; Ur, C.*; Urban, W.*; et al.
Journal of Instrumentation (Internet), 12(11), p.P11003_1 - P11003_33, 2017/11
被引用回数:46 パーセンタイル:85.14(Instruments & Instrumentation)A highly efficient array of high-purity germanium (HPGe) detectors was developed and operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of
-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 10
ns
cm
at the target position and negligible neutron halo. The target was surrounded by an array of eight to ten anti-Compton shielded EXOGAM Clover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr
:(Ce) detectors from the FATIMA collaboration.
-delayed fission of
AmWilson, G. L.*; 武山 美麗*; Andreyev, A. N.; Andel, B.*; Antalic, S.*; Catford, W. N.*; Ghys, L.*; 羽場 宏光*; He
berger, F. P.*; Huang, M.*; et al.
Physical Review C, 96(4), p.044315_1 - 044315_7, 2017/10
被引用回数:11 パーセンタイル:56.97(Physics, Nuclear)The exotic decay process of
-delayed fission has been studied in the neutron-deficient isotope
Am at RIKEN, Japan. The
Am nuclei were produced in the complete fusion reaction
Pb(
Al,4n)
Am and separated by using the GARIS gas-filled recoil ion separator. A lower limit for the
-delayed fission probability larger than 0.30 was deduced, which so far is the highest value among all known nuclei exhibiting this decay mode.
Smith, E. D. B.*; 田中 佳織*; 永井 佑紀
Physical Review B, 94(6), p.064515_1 - 064515_13, 2016/08
被引用回数:19 パーセンタイル:57.76(Materials Science, Multidisciplinary)銅酸化物高温超伝導体に代表される非従来型超伝導体は、様々な産業への応用が期待され世界中で盛んに研究されている。特に、高い超伝導転移温度を持つ有力な機能デバイス候補物質を探索することは、基礎応用どちらの面においても非常に重要である。本論文発表では、二次元トポロジカル超伝導体と呼ばれるスピン軌道相互作用の強い系において磁場を印加して生じる磁束格子相における電子状態を調べ、この超伝導体におけるカイラリティが磁束中の電子状態に顕著に反映されることがわかった。なお、上記課題の解決にあたり、磁場下の超伝導体を精度よく取り扱うための多項式展開手法を用いた並列シミュレーションコードの開発を行い、自己無撞着に安定に電子状態を計算することに成功した。本論文発表では、新しい機能デバイス候補物質である界面トポロジカル超伝導体の磁場下での特性を調べることができた。これらの結果は、磁場下でも安定なデバイス開発に資する成果であり、広く原子力分野のためのシミュレーション基盤開発にも資する成果である。
Gaffney, L. P.*; Robinson, A. P.*; Jenkins, D. G.*; Andreyev, A. N.; Bender, M.*; Blazhev, A.*; Bree, N.*; Bruyneel, B.*; Butler, P.*; Cocolios, T. E.*; et al.
Physical Review C, 91(6), p.064313_1 - 064313_11, 2015/06
被引用回数:11 パーセンタイル:56.65(Physics, Nuclear)Radioactive ion beams of
Rn were studied by means of low-energy Coulomb excitation at REX-ISOLDE, CERN. The electric-quadrupole (E2) matrix elements connecting the first excited 2
to the ground state of these nuclei was extracted, which permits to determine the collectivity of these isotopes, which in both cases is deduced to be weak, as expected from the low-lying level-energy scheme. Comparisons were also made with beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced.
Ni; Spectroscopy of the N=49 isotope
ZnOrlandi, R.; M
cher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.
Physics Letters B, 740, p.298 - 302, 2015/01
被引用回数:33 パーセンタイル:85.42(Astronomy & Astrophysics)Single-neutron states in
Zn have been populated using the reaction
Zn(d,p) at REX-Isolde, CERN. The analysis reveals that the lowest excited states in
Zn lie at approximately 1 MeV, and involve neutron orbits above the N=50 shell gap. A 5/2
configuration was assigned to the 983-keV state. Comparison with large-scale shell model calculations supports a robust neutron N=50 shell closure for
Ni. These data constitute an important step towards the understanding the magicity of
Ni and the structure of nuclei in the region.
value in
KrR
gis, J.-M.*; Jolie, J.*; Saed-Samii, N.*; Warr, N.*; Pfeiffer, M.*; Blanc, A.*; Jentschel, M.*; K
ster, U.*; Mutti, P.*; Soldner, T.*; et al.
Physical Review C, 90(6), p.067301_1 - 067301_4, 2014/12
被引用回数:24 パーセンタイル:78.42(Physics, Nuclear)A smooth onset of collectivity in
Kr has been determined from reported
and E(2
) values. This is in contrast to the sudden onset in even-even Zr, Mo, and Sr isotopes. Our objective was to complete the systematics by determining the
value in
Kr, which was produced by cold-neutron-induced fission of
U. The lifetime of the 2
state in
Kr was measured via the electronic
timing technique using the EXILL and FATIMA spectrometers. Based on the measured mean lifetime of
= 15(10) ps, the
value of 13
W.u. in
Kr is determined for the first time and the smooth onset of deformation in the even-even Kr isotopes beyond neutron number N=50 is confirmed.
Chadwick, M. B.*; Herman, M.*; Oblo
insk
, P.*; Dunn, M. E.*; Danon, Y.*; Kahler, A. C.*; Smith, D. L.*; Pritychenko, B.*; Arbanas, G.*; Arcilla, R.*; et al.
Nuclear Data Sheets, 112(12), p.2887 - 2996, 2011/12
被引用回数:2403 パーセンタイル:99.99(Physics, Nuclear)原子力科学・技術の利用分野ための評価済み核データライブラリーENDF/B-VII.1を公開した。米国核データ評価委員会が中心となって評価・整備したこの最新ライブラリーは、前バージョン(ENDF/B-VII.0)公開以後に得られた原子核理論や実験に関する知見を反映した中性子断面積,共分散,核分裂収率や崩壊データ等を格納している。ライブラリーの主な更新内容は、核種数の拡大、共分散データの拡充、R行列理論に基づく軽核の共鳴パラメータ評価、中重核やアクチノイドデータの改訂等である。核外輸送コードMCNPによるベンチマーク解析を行った結果、臨界予測性能等のパフォーマンスが向上した。
MgDaecon, A. N.*; Smith, J. F.*; Freeman, S. J.*; Janssens, R. V. F.*; Carpenter, M. P.*; Hadinia, B.*; Hoffman, C. R.*; Kay, B. P.*; Lauritsen, T.*; Lister, C. J.*; et al.
Physical Review C, 82(3), p.034305_1 - 034305_7, 2010/09
被引用回数:24 パーセンタイル:76.46(Physics, Nuclear)
Mgは、中性子数20の魔法数が消滅する「逆転の島」と呼ばれている領域の境界にあたり、その詳しい核構造は興味が持たれている。この研究では、アルゴンヌ国立研究所において
Mgの励起状態を
C(
O,2
)反応にて生成し、そこからの脱励起
線を観測することによってエネルギー準位を構築した。その結果、励起エネルギー2-4MeV領域に魔法数消滅が起きないことを前提とした理論計算では得られない状態が複数観測された。モンテカルロ殻模型による大規模計算と比較したところ、これらの状態は、2個の中性子が中性子数20の殻ギャップを超えて励起した状態と対応させることができた。すなわち、
Mgではかなり低い励起エネルギーに殻ギャップを超えた励起状態が存在することが明らかとなり、「逆転の島」の境界に属することがはっきりした。
Neall, F. B.*; Smith, P. A.*
JNC TY1400 2004-001, 144 Pages, 2004/05
第2次取りまとめの安全評価に対する考察を行った。その結果、第2次取りまとめは、日本における高レベル放射性廃棄物の安全な処分に向けてサイト選定及び処分場建設が実現可能であるという、明確かつ根拠のあるメッセージを提示していることが示された。
Anghel, A.*; 高橋 良和; Smith, S.*; Pourrahimi, S.*; Zhelamskij, M.*; Blau, B.*; Fuchs, A.*; Heer, B.*; 濱田 一弥; Fujisaki, H.*; et al.
Fusion Technology 1996, p.185 - 190, 1996/00
ITERタスクの一貫として行われたクエンチ試験(QUELL)は、1/6の縮小導体を約100m用いて導体がクエンチした時の導体のふるまいを観測し、このデータを用いてコンピュータの解析コードを確立することと、クエンチ検出システムを開発することを目的として、行われた。本論文においては、クエンチ時の常伝導部の伝播の結果(伝播速度、温度上昇、圧力上昇等)及びクエンチ検出システムの性能について報告する。
Sn studied via the
Sn(d,t)
Sn reactionOrlandi, R.; Pain, S. D.*; Bardayan, D. W.*; Gross, C. J.*; Smith, M. S.*; Jungclaus, A.*; Ahn, S.*; Jones, K. L.*; Pittman, S. T.*; Schmitt, K. T.*; et al.
no journal, ,
Knowledge of single-particle energies in the vicinity of exotic doubly-magic nuclei is of critical importance to understand evolution of nuclear structure. In the present work, the
Sn(d,t)
Sn reaction (Q=-1.055 MeV) was studied in inverse kinematics at HRIBF of Oak Ridge National Laboratory. The
Sn ISOL beam was post-accelerated to an energy of 4.39 MeV/u using the ORNL HRIBF accelerator. The beam (average intensity of
1.2e4 pps) impinged on a
250
g/cm
deuterated polyethylene target, for approximately 4 days. Ejected tritons were detected using the Super ORRUBA array of segmented Si telescopes. Low-lying states in
Sn were populated in the experiment. Preliminary results will be shown.
Zn and the structure of
NiOrlandi, R.; M
cher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.
no journal, ,
Single-neutron states in the
= 49 isotope
Zn were populated in the
Zn(d,p)
Zn transfer reaction at REX-ISOLDE, CERN. The combined detection of protons ejected in the reaction and of
rays emitted by
Zn permitted the identification of the lowest-lying 5/2
and 1/2
excited states. The analysis of proton angular distributions links these states to a significant amount of single-particle strength around 1 MeV, and specifically to the
d
and
s
neutron orbits, which lie above the
= 50 neutron shell gap. Comparison with large-scale-shell-model calculations supports a robust
= 50 shell-closure for
Ni. These data constitute a considerable step towards the understanding of the magicity of
Ni and of the structure of isotopes in the region.