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Journal Articles

Spectroscopy of strongly deformed $$^{32}$$Ne by proton knockout reactions

Murray, I.*; MacCormick, M.*; Bazin, D.*; Doornenbal, P.*; Aoi, Nori*; Baba, Hidetada*; Crawford, H. L.*; Fallon, P.*; Li, K.*; Lee, J.*; et al.

Physical Review C, 99(1), p.011302_1 - 011302_7, 2019/01

理化学研究所のRI Beam Factory(RIBF)にて中性子過剰核$$^{32}$$Neの低励起状態を1陽子あるいは2陽子ノックアウト反応によって生成し、そこからの脱励起ガンマ線の測定によって、エネルギー準位を構築した。1410(15)keVのガンマ線を初めて測定し、反応断面積の系統性などから$$4^+_1$$から$$2^+_1$$への遷移に対応すると提案した。既に知られている$$2^+_1$$準位を用いて、$$4^+_1$$$$2^+_1$$の励起エネルギー比2.99(6)が得られた。この値は、回転スペクトルの値に近く、$$^{32}$$Neは強く変形していることがわかった。この実験結果は、大規模殻模型計算の結果とよく一致した。

Journal Articles

$$g$$-factor measurement of the 2738 keV isomer in $$^{135}$$La

Laskar, Md. S. R.*; Saha, S.*; Palit, R.*; Mishra, S. N.*; Shimizu, Noritaka*; Utsuno, Yutaka; Ideguchi, Eiji*; Naik, Z.*; Babra, F. S.*; Biswas, S.*; et al.

Physical Review C, 99(1), p.014308_1 - 014308_6, 2019/01

タタ基礎物理学研究所の重イオン加速器にて、$$^{11}$$B($$^{128}$$Te, 4n)$$^{135}$$La反応によって$$^{135}$$Laの励起状態を生成し、2738keVにあるアイソマーの$$g$$因子を時間微分型摂動角分布(TDPAD)法によって測定した。得られた$$g$$因子の値は$$-0.049(3)$$であった。このアイソマーの核構造を理解するため、$$^{135}$$Laに対し、大規模殻模型計算を行った。殻模型計算は低励起状態のバンド構造を非常によく再現し、2738keVのアイソマーのスピンパリティは$$23/2^+$$であることを強く示唆する結果が得られた。このアイソマーは、$$^{134}$$Baの$$10^+_1$$$$d_{5/2}$$軌道にいる陽子が結合してできる配位が主であると解釈された。

JAEA Reports

Proceedings of the 2017 Symposium on Nuclear Data; November 16-17, 2017, iVil, Tokai-mura, Ibaraki, Japan

Nishio, Katsuhisa; Utsuno, Yutaka; Chiba, Satoshi*; Koura, Hiroyuki; Iwamoto, Osamu; Nakamura, Shoji

JAEA-Conf 2018-001, 226 Pages, 2018/12

JAEA-Conf-2018-001.pdf:22.81MB

The 2017 Symposium on Nuclear Data was held at iVil in Tokai on November 16-17, 2017. The symposium was hosted by the Nuclear Data Division of the Atomic Energy Society of Japan (AESJ) and Advanced Science Research Center of Japan Atomic Energy Agency, and co-hosted by Japanese Nuclear Data Committee of AESJ and North Kanto Branch of AESJ. In the symposium, a tutorial was given by Prof. Rykaczewski (ORNL) "New nuclear data from total absorption spectroscopy and beta-delayed neutron measurements", as well as six oral sessions, "Nuclear Physics and Nuclear Data" (two sessions), "Nuclear Theory and Nuclear Data", "Reactors" and "Nuclear Data and Their Applications" (two sessions). In addition, recent advances in experiment, theory, evaluation, benchmark, and application were presented in the poster session. The symposium had 79 participants, who contributed to very active and fruitful discussions. This report consists of 37 papers, including those of 14 oral and 23 poster presentations.

Journal Articles

Evaluation of photocatalytic abilities by variation of conductivity and dimethyl sulfoxide; Photocatalytically active TiO$$_{2}$$-coated wire mesh prepared via a double-layer coating method

Mori, Masanobu*; Sugita, Tsuyoshi; Fujii, Kengo*; Yamazaki, Taiki*; Isaka, Mayu*; Kobayashi, Kentaro*; Iwamoto, Shinji*; Itabashi, Hideyuki*

Analytical Sciences, 34(12), p.1449 - 1453, 2018/12

The photocatalyst coating stainless-steel wire mesh (TiO$$_{2}$$-WM) was prepared by double-layer coating method. The TiO$$_{2}$$-WM was evaluated using flow analytical system, which included the reactor and conductimetric detector (FAS-CD). The DMSO decomposition test through the FAS-CD reveal that photocatalytst was stable coating on the stainless-steel wire mesh.

Journal Articles

Phenomenological approach to study the degree of the itinerancy of the 5$$f$$ electrons in actinide ferromagnets with spin fluctuation theory

Tateiwa, Naoyuki; Posp$'i$$v{s}$il, J.*; Haga, Yoshinori; Sakai, Hironori; Matsuda, Tatsuma*; Yamamoto, Etsuji

Progress in Nuclear Science and Technology (Internet), 5, p.104 - 107, 2018/12

Uranium ferromagnetic superconductors UGe$$_2$$, URhGe and UCoGe have attracted much attention from both theoretical and experimental sides since the same 5$$f$$ electrons underlie carry both the ferromagnetism and superconductivity. Recently, we have analysed 69 uranium, 7 neptunium, and 4 plutonium ferromagnets with spin fluctuation theory originally developed for researches on itinerant ferromagnets in the 3$$d$$ transition metals and their intermetallics. The applicability of the spin fluctuation theory to the actinide 5$$f$$ system has been confirmed and the itinerant character of the 5f electrons is suggested in the actinide ferromagnets. In this conference, two results will be shown. One is the results of the analyses on 80 actinide ferromagnets and the other is the pressure dependence of the spin fluctuation parameters in UGe$$_2$$.

Journal Articles

Online chemical adsorption studies of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; Asai, Masato; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$$_{2}$$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$$_{2}$$ surface at room temperature. On the other hand, the Hg did not adsorb on the SiO$$_{2}$$ surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl.

Journal Articles

Electric field control of magnetic domain wall motion via modulation of the Dzyaloshinskii-Moriya interaction

Koyama, Tomohiro*; Nakatani, Yoshinobu*; Ieda, Junichi; Chiba, Daichi*

Science Advances (Internet), 4(12), p.eaav0265_1 - eaav0265_5, 2018/12

We show that the electric field (EF) can control the magnetic domain wall (DW) velocity in a Pt/Co/Pd asymmetric structure. With the application of a gate voltage, a significant change in DW velocity up to 50 m/s is observed, which is much greater than that observed in previous studies. Moreover, a DW velocity exceeding 100 m/s is clearly modulated. An EF-induced change in the interfacial Dzyaloshinskii-Moriya interaction (DMI) up to several percent is found to be the origin of the velocity modulation. The DMI-mediated velocity change shown here is a fundamentally different mechanism from that caused by EF-induced anisotropy modulation. Our results will pave the way for the electrical manipulation of spin structures and dynamics via DMI control, which can enhance the performance of spintronic devices.

Journal Articles

High-energy spin fluctuation in low-T$$_{c}$$ iron-based superconductor LaFePO$$_{0.9}$$

Ishikado, Motoyuki*; Shamoto, Shinichi; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Hong, T.*; Mutka, H.*

Scientific Reports (Internet), 8, p.16343_1 - 16343_6, 2018/11

Spin fluctuations are widely believed to play an important role as one of the most possible mechanisms for unconventional high-temperature superconductors. Here, the spin fluctuation in LaFePO$$_{0.9}$$ is found at high energies such as 30-50 meV with comparable intensity to an optimally doped LaFeAs(O,F).

Journal Articles

Superconductivity in a multiorbital model for the $$Gamma_3$$ crystalline electric field state

Kubo, Katsunori

AIP Advances (Internet), 8(10), p.101313_1 - 101313_6, 2018/10

A cubic system with the $$Gamma_3$$ cubic crystalline electric field (CEF) state is an ideal system to investigate multipole physics, since it does not have dipole but has higher-order multipoles such as quadrupole and octupole. In addition, superconductivity has been observed in PrT$$_2$$X$$_{20}$$ (T = Ir, Rh, X = Zn; T = Ti, V, X = Al) systems with the $$Gamma_3$$ CEF ground state. To approach these phenomena theoretically, we consider a model composed of f electrons with the total angular momentum $$j=5/2$$. From this model, we have derived multipole interactions for the $$Gamma_3$$ systems. In the present study, we investigate superconductivity in the same model. We apply random phase approximation for superconductivity in a multiorbital system to the present model. Then, we have obtained a d-wave spin-singlet state. We will discuss the relevance of the present theory to the PrT$$_2$$X$$_{20}$$ superconductors.

Journal Articles

Preliminary evaluation of local structure and speciation of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcite using the L$$_{3}$$-Edge X-ray absorption near edge structure spectra

Ota, Atsuyuki*; Tanaka, Kazuya; Tsuno, Hiroshi*

Journal of Physical Chemistry A, 122(41), p.8152 - 8161, 2018/10

We investigated the application of L$$_{3}$$-edge XANES spectra to the local structural analysis of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcium carbonate. For each lanthanoid, the full width at half maximum (FWHM) values of lanthanoid compounds roughly decreased with increasing coordination numbers. However, they did not strictly reflect the local coordination sphere of the lanthanoid complex, but were rather sensitive to their chemical forms. The relationship between the magnitude of the FWHM values was determined by the crystal field splitting or degeneracy of 5d orbitals. The systematic variation of FWHM can be explained by the ligand strength of the ligand molecules (-H$$_{2}$$O$$^{0}$$, -O$$^{-}$$, -OH$$^{-}$$, -CO$$_{3}$$$$^{2-}$$, -Cl$$^{-}$$, and -O$$^{2-}$$) that cause the crystal field splitting. Therefore, the FWHM values of L$$_{3}$$-edge XANES of lanthanoid compounds may be more useful in speciation analysis rather than structural analysis such as EXAFS.

Journal Articles

Spin torques and electrical voltage generation in antiferromagnetic nanotextures

Yamane, Yuta*; Ieda, Junichi

Magune, 13(5), p.235 - 241, 2018/10

We overview the recent theoretical development on spin-transfer torque in antiferromagnetic nanostructures and related subjects. As antiferromagnetic materials are generating more attention lately due to their potential to play pivotal roles in spintronics applications, demands are rising for reliable methods to control and detect antiferromagnetic textures and their dynamics. While antiferromagnets are largely insensitive to external magnetic fields in general, electrical means are proving to be capable of offering promising ways to access the antiferromagnetic dynamics. We discuss in this article the possibility of manipulation and observation of dynamical antiferromagnetic textures by electrical current and voltage.

Journal Articles

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

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Ogawa, Tatsuhiko; 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

We have developed a new setup to measure prompt fission $$gamma$$-ray spectra in neutron induced fission up to energies sufficient to reveal the structure associated with giant dipole resonances of fission fragments. The setup consists of multi-wire proportional counters, to detect both fission fragments in coincidence, and two large volume (101.6 mm in diameter and 127.0 mm in length) LaBr$$_{3}$$(Ce) scintillators, to measure the $$gamma$$-rays. The setup was used to obtain the prompt fission $$gamma$$-ray spectrum for thermal neutron induced fission of $$^{235}$$U at the PF1B cold-neutron beam facility of the Institut Laue-Langevin, Grenoble, France. We have successfully measured the $$gamma$$-ray spectrum up to energies of about 20 MeV, what extends the currently known $$gamma$$-ray spectrum limit to higher energies by approximately a factor of two.

Journal Articles

Quark model estimate of hidden-charm pentaquark resonances

Hiyama, Emiko; Hosaka, Atsushi; Oka, Makoto; Richard, J.-M.*

Physical Review C, 98(4), p.045208_1 - 045208_8, 2018/10

A quark model, which reproduces the ground-state mesons and baryons, i.e., the threshold energies, is applied to the $$qqqcbar c$$ configurations, where $$q$$ is a light quark and $$c$$ the charmed quark. In the calculation, several open channels are explicitly included such as $$J/psi +N$$, $$eta_c+N$$, $$Lambda_c +D$$, etc. To distinguish genuine resonances and estimate their width, we employ Gaussian Expansion Method supplemented by the real scalingmethod (stabilization). No resonance is found at the energies of the $$P_c(4380)$$ and $$P_c(4450)$$ pentaquarks. On the other hand, there is a sharp resonant state at 4690 MeV with $$J=1/2^-$$ state and another one at 4920 MeV with $$J=3/2^-$$ state, which have a compact structure.

Journal Articles

Liquid-phase chemistry of rutherfordium (Rf), dubnium (Db) and seaborgium (Sg)

Nagame, Yuichiro

Radioisotopes, 67(10), p.507 - 526, 2018/10

Recent studies of the chemical separation and characterization experiments of the first three transactinide elements, rutherfordium (Rf), dubnium (Db) and seaborgium (Sg), conducted atom-at-a-time in liquid phases, are reviewed. A short description on experimental techniques based on partition methods, specifically automated rapid chemical separation systems, as well as on assessment of role of relativistic effects is also given. Perspectives for liquid phase chemistry experiments on heavier elements are briefly discussed.

Journal Articles

Structure determination of germanene by total-reflection high-energy positron diffraction

Fukaya, Yuki

Yodenshi Kagaku, (11), p.41 - 44, 2018/09

本研究では、全反射高速陽電子回折(TRHEPD)を用いて、ゲルマニウムの2次元原子シートであるゲルマネンの原子配置を決定した。回折強度の定量解析から、Al(111)基板上に合成したゲルマネンは、先行研究で予測されたような単位格子中2個のGe原子が突出した対称的なバックリング構造ではなく、Ge原子1個だけが突出した非対称な構造をとることがわかった。

Journal Articles

Extraction ability of 4-benzoyl-3-phenyl-5-isoxazolone towards 4f-ions into ionic and molecular media

Atanassova, M.*; Okamura, Hiroyuki; Eguchi, Ayano; Ueda, Yuki; Sugita, Tsuyoshi; Shimojo, Kojiro

Analytical Sciences, 34(8), p.973 - 978, 2018/08

 Times Cited Count:2

The distribution constants of 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) and deprotonated one (PBI$$^{-}$$) between hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C$$_{1}$$C$$_{4}$$im][Tf$$_{2}$$N]) and aqueous phases were determined, together with the acid-dissociation constant of HPBI. The solvent extraction of three selected lanthanoid ions (La$$^{3+}$$, Eu$$^{3+}$$, and Lu$$^{3+}$$) with HPBI from aqueous nitrate phase into [C$$_{1}$$C$$_{4}$$im][Tf$$_{2}$$N] has been investigated. Application of the ionic liquid as the extracting phase greatly enhanced the extraction performance of HPBI for lanthanoid ions compared with that in the chloroform system. The composition of the extracted species was established to be anionic tetrakis entities, Ln(PBI)$$_{4}$$$$^{-}$$, for light, middle, and heavy lanthanoid ions in an ionic environment.

Journal Articles

Occupation sites and valence states of Co dopants in (La, Co)-codoped M-type Sr ferrite; $$^{57}$$Fe and $$^{59}$$Co nuclear magnetic resonance studies

Sakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ueda, Hiroaki*; Tanioku, Yasuaki*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Takao, Kenta*; Shimoda, Aiko*; et al.

Physical Review B, 98(6), p.064403_1 - 064403_10, 2018/08

To specify preferential occupation sites of Co substituents and to clarify charge and spin states of Co ions in (La, Co)-cosubstituted hexagonal magnetoplumbite-type (M-type) Sr ferrite, $$^{57}$$Fe and $$^{59}$$Co nuclear magnetic resonance (NMR) spectra are measured under zero and external magnetic fields using powdered and single crystalline specimens. To a considerable degree, the charge compensation between La$$^{3+}$$ and Co$$^{2+}$$ works in the equal (La, Co)-codoped case, where more than half of the Co ions are considered to be present in the minority spin $$4f_1$$ sites at the center of the oxygen tetrahedra, with the $$S$$ = 3/2 state carrying a small orbital moment owing to spin-orbit interaction. The remaining small number of high-spin Co$$^{2+}$$ ($$S$$ = 3/2, $$L$$ = 1) ions with unquenched orbital moments would be distributed to the other octahedral $$12k$$, $$2a$$, and $$4f_2$$ sites.

Journal Articles

Investigation of $$alpha$$ clustering with knockout reactions

Yoshida, Kazuki; Ogata, Kazuyuki*; Kanada-En'yo, Yoshiko*

Physical Review C, 98(2), p.024614_1 - 024614_6, 2018/08

In $$alpha$$ clustering studies, it is very important to probe the $$alpha$$ cluster amplitude at nuclear surface since $$alpha$$ spectroscopic factor is not necessarily a direct measure of the $$alpha$$ clustering. We consider $$^{20}$$Ne($$p$$,$$palpha$$)$$^{16}$$O and $$^{120}$$Sn($$p$$,$$palpha$$)$$^{116}$$Cd at 100 - 400 MeV within the distorted wave impulse approximation (DWIA) framework. We introduce a $textit{masking function}$ which shows how the reaction amplitude in the nuclear interior is suppressed and defines the probed region of the $$alpha$$ cluster wave function. It is clearly shown by means of the masking function that thanks to the absorption of distorting potentials, the $$alpha$$ knockout reaction probes the $$alpha$$ cluster amplitude in the nuclear surface region, which is the direct measure of well-developed $$alpha$$ cluster states.

Journal Articles

NMR study of actinide compounds; Case of actinide dioxides

Kambe, Shinsaku

Radioisotopes, 67(8), p.389 - 401, 2018/08

二酸化アクチノイド化合物AnO$$_{2}$$を例にとり、NMR法を用いた低温電子物性研究について解説する。AnO$$_2$$系では、An核とO核のNMRを観測できることが特長である。核燃料であるUO$$_{2}$$に代表されるこの系は、高温での挙動に興味が持たれることが多いが、最近、基底状態も多極子秩序という新しい電子状態であることがわかり注目されている。アクチノイド化合物低温物性の面白さを紹介する。

Journal Articles

Observation of gyromagnetic reversal

Imai, Masaki; Ogata, Yudai*; Chudo, Hiroyuki; Ono, Masao; Harii, Kazuya; Matsuo, Mamoru*; Onuma, Yuichi*; Maekawa, Sadamichi; Saito, Eiji

Applied Physics Letters, 113(5), p.052402_1 - 052402_3, 2018/07

We report direct observation of gyromagnetic reversal, which is the sign change of gyromagnetic ratio in a ferrimagnet Ho$$_3$$Fe$$_5$$O$$_{12}$$, by using the Barnett effect measurement technique at low temperatures. The Barnett effect is a phenomenon in which magnetization is induced by mechanical rotation through the coupling between rotation and total angular momentum $$J$$ of electrons. The magnetization of Ho$$_3$$Fe$$_5$$O$$_{12}$$ induced by mechanical rotation disappears at 135 K and 240 K. The temperatures correspond to the magnetization compensation temperature $$T_{rm M}$$ and the angular momentum compensation temperature $$T_{rm A}$$, respectively. Between $$T_{rm M}$$ and $$T_{rm A}$$, the magnetization flips over to be parallel against the angular momentum due to the sign change of gyromagnetic ratio. This study provides an unprecedented technique to explore the gyromagnetic properties.

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