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Journal Articles

Development of an areal density imaging for boron and other elements

Tsuchikawa, Yusuke; Kai, Tetsuya; Abe, Yuta; Oikawa, Kenichi; Parker, J. D.*; Shinohara, Takenao; Sato, Ikken

Journal of Physics; Conference Series, 2605, p.012022_1 - 012022_6, 2023/10

We developed a method to obtain the areal density distribution of boron, which has a large neutron cross section, by means of an energy resolved neutron imaging. Commonly in a measurement of elements with very high neutron sensitivity, the quantitative measurement becomes more difficult with the amount of element due to the neutron self-shielding effect. To avoid this effect, an energy-resolved method using known cross section data was attempted, and a quantitative imaging of such elements was demonstrated at the MLF of J-PARC. This presentation introduces a measurement of melted simulated-fuel assemblies obtained in the research of the Fukushima Daiichi Nuclear Power Plant after the severe accident. Energy-dependent neutron transmission rates of the samples were measured by a neutron imaging detector, and were analyzed to obtained the areal density of boron at each position.

Journal Articles

Update of Bragg edge analysis software "GUI-RITS"

Oikawa, Kenichi; Sato, Hirotaka*; Watanabe, Kenichi*; Su, Y. H.; Shinohara, Takenao; Kai, Tetsuya; Kiyanagi, Yoshiaki*; Hasemi, Hiroyuki

Journal of Physics; Conference Series, 2605, p.012013_1 - 012013_6, 2023/10

Journal Articles

Intruder configurations in $$^{29}$$Ne at the transition into the island of inversion; Detailed structure study of $$^{28}$$Ne

Wang, H.*; Yasuda, Masahiro*; Kondo, Yosuke*; Nakamura, Takashi*; Tostevin, J. A.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Poves, A.*; Shimizu, Noritaka*; Yoshida, Kazuki; et al.

Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08

 Times Cited Count:2 Percentile:79.22(Astronomy & Astrophysics)

Detailed $$gamma$$-ray spectroscopy of the exotic neon isotope $$^{28}$$Ne has been performed using the one-neutron removal reaction from $$^{29}$$Ne. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for $$^{28}$$Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N = 20 and N = 28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.

Journal Articles

Gyromagnetic bifurcation in a levitated ferromagnetic particle

Sato, Tetsuya*; Kato, Takeo*; Oue, Daigo*; Matsuo, Mamoru

Physical Review B, 107(18), p.L180406_1 - L180406_6, 2023/05

 Times Cited Count:1 Percentile:44.21(Materials Science, Multidisciplinary)

Journal Articles

Extreme chemistry of superheavy elements

Sato, Tetsuya; Nagame, Yuichiro*

Nihon Butsuri Gakkai-Shi, 78(2), p.64 - 72, 2023/02

The study of the chemistry of superheavy elements, which are located in the heavy extremes of the periodic table, has made considerable progress over the past 20 years, and new approaches based on various ideas have recently been developed. Research groups in Japan have also made significant contributions to the development of research on superheavy elements. Recently, notable results have been reported for the transactinide elements rutherfordium (element 104), dubnium (element 105), and seaborgium (element 106), and the heavy actinides with atomic numbers exceeding 100. The review will focus on the recent main results of these elements. This review outlines the main recent results and touches on future prospects.

Journal Articles

New $$K$$ isomers in $$^{248}$$Cf

Orlandi, R.; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Ito, Yuta; Suzaki, Fumi; Nagame, Yuichiro*; et al.

Physical Review C, 106(6), p.064301_1 - 064301_11, 2022/12

 Times Cited Count:1 Percentile:28.09(Physics, Nuclear)

Journal Articles

Spatial distribution and preferred orientation of crystalline microstructure of lead-bismuth eutectic

Ito, Daisuke*; Sato, Hirotaka*; Odaira, Naoya*; Saito, Yasushi*; Parker, J. D.*; Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi

Journal of Nuclear Materials, 569, p.153921_1 - 153921_6, 2022/10

 Times Cited Count:1 Percentile:27.23(Materials Science, Multidisciplinary)

Journal Articles

On the adsorption and reactivity of element 114, flerovium

Yakushev, A.*; Lens, L.*; D$"u$llmann, Ch. E.*; Khuyagbaatar, J.*; J$"a$ger, E.*; Krier, J.*; Runke, J.*; Albers, H. M.*; Asai, Masato; Block, M.*; et al.

Frontiers in Chemistry (Internet), 10, p.976635_1 - 976635_11, 2022/08

 Times Cited Count:11 Percentile:81.01(Chemistry, Multidisciplinary)

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. The first chemical experiment on Fl suggested that Fl is a noble-gas-like element, while the second studies suggested that Fl has a volatile-metal-like character. To obtain more reliable conclusion, we performed further experimental studies on Fl adsorption behavior on Si oxide and gold surfaces. The present results suggest that Fl is highly volatile and less reactive than the volatile metal, Hg, but has higher reactivity than the noble gas, Rn.

Journal Articles

Novel $$^{90}$$Sr analysis of environmental samples by ion-laser interaction mass spectrometry

Honda, Maki; Martschini, M.*; Marchhart, O.*; Priller, A.*; Steier, P.*; Golser, R.*; Sato, Tetsuya; Tsukada, Kazuaki; Sakaguchi, Aya*

Analytical Methods, 14(28), p.2732 - 2738, 2022/07

 Times Cited Count:2 Percentile:41.58(Chemistry, Analytical)

The sensitive $$^{90}$$Sr analysis with accelerator mass spectrometry (AMS) was developed for the advances of environmental radiology. One advantage of AMS is the ability to analyze various environmental samples with $$^{90}$$Sr/$$^{88}$$Sr atomic ratios of 10$$^{-14}$$ in a simple chemical separation. Three different IAEA samples with known $$^{90}$$Sr concentrations (moss-soil, animal bone, Syrian soil: 1 g each) were analyzed to assess the validity of the chemical separation and the AMS measurement. The $$^{90}$$Sr measurements were conducted on the AMS system combined with the Ion Laser InterAction MasSpectrometry (ILIAMS) setup at the University of Vienna, which has excellent isobaric separation performance. The isobaric interference of $$^{90}$$Zr in the $$^{90}$$Sr AMS was first removed by chemical separation. The separation factor of Zr in two-step column chromatography with Sr resin and anion exchange resin was 10$$^{6}$$. The $$^{90}$$Zr remaining in the sample was removed by ILIAMS effectively. This simple chemical separation achieved a limit of detection $$<$$ 0.1 mBq in the $$^{90}$$Sr AMS, which is lower than typical $$beta$$-ray detection. The agreement between AMS measurements and nominal values for the $$^{90}$$Sr concentrations of IAEA samples indicated that the new highly-sensitive $$^{90}$$Sr analysis in the environmental samples with AMS is reliable even for high matrix samples of soil and bone.

Journal Articles

Chemistry of the elements at the end of the actinide series using their low-energy ion-beams

Sato, Tetsuya; Nagame, Yuichiro*

Radiochimica Acta, 110(6-9), p.441 - 451, 2022/07

 Times Cited Count:1 Percentile:27.23(Chemistry, Inorganic & Nuclear)

We describe our recent achievements in the effective production of low-energy ion-beams of the elements at the end of the actinide series, fermium (Fm, atomic number Z = 100), mendelevium (Md, Z = 101), nobelium (No, Z = 102), and lawrencium (Lr, Z = 103), using a surface ionization ion-source installed in the ISOL (Isotope Separator On-Line) at the Tandem accelerator facility of JAEA (Japan Atomic Energy Agency). Then the successful measurements of the first ionization potentials (IP$$_1$$) of these elements with the ISOL setup are reviewed. The measured IP$$_1$$ values increased up to No via Fm and Md, while that of Lr was the lowest among the actinides. Based on the variation of the IP1 values of the heavy actinides with the atomic number in comparison with those of the heavy lanthanides, the results clearly demonstrated that the 5f orbitals are fully filled at No, and the actinide series ends with Lr. Furthermore, the IP$$_1$$ value of Lr provoked controversy over its position in the Periodic Table, so a short introduction to this issue is presented. The feasibility of the extension of chemical studies to still heavier elements with their ion-beams generated by ISOL is briefly discussed.

Journal Articles

Fluctuation theorem for spin transport at insulating ferromagnetic junctions

Sato, Tetsuya*; Tatsuno, Masahiro*; Matsuo, Mamoru; Kato, Takeo*

Journal of Magnetism and Magnetic Materials, 546, p.168814_1 - 168814_6, 2022/03

 Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)

Journal Articles

Application of a novel gas phase synthesis approach to carbonyl complexes of accelerator-produced 5d transition metals

G$"o$tz, M.*; Yakushev, A.*; G$"o$tz, S.*; Di Nitto, A.*; D$"u$llmann, Ch. E.*; Asai, Masato; Kindler, B.*; Krier, J.*; Lommel, B.*; Nagame, Yuichiro*; et al.

Radiochimica Acta, 110(2), p.75 - 86, 2022/02

 Times Cited Count:2 Percentile:29.53(Chemistry, Inorganic & Nuclear)

The study of volatile superheavy element carbonyl complexes requires more efficient methods because the yield of transactinide elements decreases with increasing atomic number. This is achieved by using a newly developed double chamber system to separate the recoil chamber and the reaction one, thereby avoiding the decomposition of reactive molecules by the projectile ion beam, which hinders the synthesis of carbonyl complexes. The feasibility of this method was verified by synthesizing 5d metal short-lived isotopes as homologous element isotopes of the light transactinide elements Sg, Bh, Hs, and Mt at the Japan Atomic Energy Agency tandem accelerator and conducting model experiments.

Journal Articles

Towards $$CP$$-violation studies on superheavy molecules; Theoretical and experimental perspectives

Mitra, R.*; Prasannaa, V. S.*; Garcia Ruiz, R. F.*; Sato, Tetsuya; Abe, Minori*; Sakemi, Yasuhiro*; Das, B. P.*; Sahoo, B. K.*

Physical Review A, 104(6), p.062801_1 - 062801_9, 2021/12

 Times Cited Count:2 Percentile:22.84(Optics)

We provide detailed theoretical studies of quantities relevant to the electron electric dipole moment (eEDM) and nucleus-electron scalar-pseudoscalar interactions in diatomic molecules containing superheavy lawrencium nuclei. The sensitivity to parity and time (or, equivalently, $$CP$$) reversal violating properties is studied for different neutral and ionic molecules. The effective electric fields in these systems are found to be about 3$$sim$$4 times larger than other known molecules on which eEDM experiments are being performed. Similarly, these superheavy molecules exhibit an enhancement of more than 3 times for $$CP$$-violating scalar-pseudoscalar nucleus-electron interactions. Our preliminary analysis using the Woods-Saxon nuclear model also demonstrates that these results are sensitive to the diffuse surface interactions inside the Lr nucleus.

Journal Articles

First study on Nihonium (Nh, Element 113) chemistry at TASCA

Yakushev, A.*; Lens, L.*; D$"u$llmann, C. E.*; Block, M.*; Nagame, Yuichiro*; Sato, Tetsuya; Toyoshima, Atsushi*; 42 of others*

Frontiers in Chemistry (Internet), 9, p.753738_1 - 753738_9, 2021/11

 Times Cited Count:11 Percentile:64.63(Chemistry, Multidisciplinary)

Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p$$_{1/2}$$ sub-shell, which originates from a large spin-orbit splitting between the 7p$$_{1/2}$$ and 7p$$_{3/2}$$ orbitals. One unpaired electron in the outermost 7p$$_{1/2}$$ sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.

Journal Articles

The $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross section from the surrogate ratio method and its effect on the $$^{60}$$Fe nucleosynthesis

Yan, S. Q.*; Li, X. Y.*; Nishio, Katsuhisa; Lugaro, M.*; Li, Z. H.*; Makii, Hiroyuki; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; Hirose, Kentaro; et al.

Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10

 Times Cited Count:1 Percentile:8.24(Astronomy & Astrophysics)

Journal Articles

Chemical characterization of a volatile dubnium compound, DbOCl$$_3$$

Chiera, N. M.*; Sato, Tetsuya; Eichler, R.*; Tomitsuka, Tomohiro; Asai, Masato; Adachi, Sadia*; Dressler, R.*; Hirose, Kentaro; Inoue, Hiroki*; Ito, Yuta; et al.

Angewandte Chemie; International Edition, 60(33), p.17871 - 17874, 2021/08

 Times Cited Count:3 Percentile:21.36(Chemistry, Multidisciplinary)

The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350 - 600 $$^circ$$C. Under the exact same chemical conditions, comparative studies with the lighter homologs of group-5 in the Periodic Table clearly indicate the volatility sequence being NbOCl$$_3 > $$ TaOCl$$_3 geq$$ DbOCl$$_3$$. From the obtained experimental results, thermochemical data for DbOCl$$_3$$ were derived. The present study delivers reliable experimental information for theoretical calculations on the chemical properties of transactinides.

Journal Articles

Behavior of tritium release from a stainless vessel of the mercury target as a spallation neutron source

Kasugai, Yoshimi; Sato, Koichi; Takahashi, Kazutoshi*; Miyamoto, Yukihiro; Kai, Tetsuya; Harada, Masahide; Haga, Katsuhiro; Takada, Hiroshi

JPS Conference Proceedings (Internet), 33, p.011144_1 - 011144_6, 2021/03

A spallation neutron source with a mercury target has been in operation at the Materials and Life Science Experimental Facility of J-PARC since 2008. The target vessel made of stainless steel is required to be exchanged periodically due to radiation damage etc. In this presentation, tritium gas release observed in the first series of exchange work in 2011 and the analytical results will be shown.

Journal Articles

Visualization of the boron distribution in core material melting and relocation specimen by neutron energy resolving method

Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken

JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03

Journal Articles

Feasibility study of PGAA for boride identification in simulated melted core materials

Tsuchikawa, Yusuke; Abe, Yuta; Oishi, Yuji*; Kai, Tetsuya; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Kimura, Atsushi; Nakamura, Shoji; Harada, Masahide; et al.

JPS Conference Proceedings (Internet), 33, p.011074_1 - 011074_6, 2021/03

In the decommissioning of the Fukushima-Daiichi (1F) Nuclear Power Plant, it is essential to understand characteristics of the melted core materials. The estimation of boride in the real debris is of great importance to develop safe debris removal plans. Hence, it is required to investigate the amount of boron in the melted core materials with nondestructive methods. Prompt gamma-ray activation analysis (PGAA) is one of the useful techniques to determine the amount of borides by means of the 478 keV prompt gamma-ray from neutron absorption reaction of boron. Moreover, it is well known that the width of the 478 keV gamma-ray peak is typically broadened due to the Doppler effect. The degree of the broadening is affected by coexisting materials, and can be recognized by the width of the prompt gamma-ray peak. As a feasibility study, the prompt gamma-ray from boride samples were measured using the ANNRI, NOBORU, and RADEN beamlines at the Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Complex (J-PARC).

Journal Articles

Measurement of Doppler broadening of prompt gamma-rays from various zirconium- and ferro-borons

Tsuchikawa, Yusuke; Kai, Tetsuya; Abe, Yuta; Oishi, Yuji*; Sun, Y.*; Oikawa, Kenichi; Nakatani, Takeshi; Sato, Ikken

Nuclear Instruments and Methods in Physics Research A, 991, p.164964_1 - 164964_5, 2021/03

 Times Cited Count:1 Percentile:17.58(Instruments & Instrumentation)

Peak shape analysis was performed for the energy spectra of Doppler-broadened prompt $$gamma$$-rays generated by neutron capture reactions with various boride or boron samples. Significant differences were observed between nonmetallic and metallic borides. Minor differences between the peak shapes of prompt $$gamma$$-rays from zirconium- and ferro-borons were evaluated by a peak fitting method. The identification of zirconium- and ferro-borons and other types of borides was estimated.

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