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, and X-ray spectrum analysisOshima, Masumi*; Goto, Jun*; Hayakawa, Takehito*; Asai, Masato; Kin, Tadahiro*; Shinohara, Hirofumi*
Isotope News, (790), p.19 - 23, 2023/12
When analyzing samples that contain many radionuclides at various concentrations, such as radioactive waste or fuel debris, it is difficult to apply general spectrum analysis methods and is necessary to chemically separate each nuclide before quantifying it. The chemical separation is especially essential for analysis using a liquid scintillation counter (LSC). In this report, the authors explain the newly developed spectral determination method (SDM) in which the entire spectrum is fitted to quantify radioactivity of nuclides mixed in a sample. By applying the SDM to - and X-ray spectrum measured by LSC and -ray spectrum measured by Ge detector simultaneously, the authors demonstrated that radioactivity of 40 radionuclides mixed in a sample at concentrations varying by two orders could be quantified, which is useful to simplify chemical separation process in radionuclide quantification.
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：2 Percentile：14.88(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 
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
TaOCl
DbOCl. From the obtained experimental results, thermochemical data for DbOCl were derived. The present study delivers reliable experimental information for theoretical calculations on the chemical properties of transactinides.
Hagiwara, Hiroki; Nakanishi, Takahiro; Konishi, Hiromi*; Tsuruta, Tadahiko; Misono, Toshiharu; Fujiwara, Kenso; Kitamura, Akihiro
Journal of Environmental Radioactivity, 220-221, p.106294_1 - 106294_9, 2020/09
Times Cited Count：0 Percentile：0(Environmental Sciences)Hagiwara, Hiroki; Konishi, Hiromi*; Nakanishi, Takahiro; Fujiwara, Kenso; Iijima, Kazuki; Kitamura, Akihiro
Journal of Environmental Radioactivity, 211, p.106042_1 - 106042_10, 2020/01
Times Cited Count：3 Percentile：14.71(Environmental Sciences)Oshima, Masumi*; Yamaguchi, Yurie*; Asai, Masato; Tsukada, Kazuaki; Goto, Jun*; Bamba, Shigeru*; Bi, C.*; Morimoto, Takao*
Journal of Nuclear Science and Technology, 56(9-10), p.866 - 872, 2019/09
Times Cited Count：1 Percentile：11.15(Nuclear Science & Technology)Sensitivity of charged particle activation analysis with 8 MeV proton beam was studied for determination of 35 long-lived radioactive nuclides. Reaction cross sections for those nuclides were estimated with ALICE-91 code and isomer yield ratios were estimated from those of neighboring isotopes by taking into account their spins and parities. It was found that the proposed charged particle activation analysis should show high sensitivity for the determination of several hardly measurable nuclides with long half-lives such as 
Cs, 
Pu, 
I, 
Sn, 
Mo, 
Pd, 
U, 
Cm, and 
Np.
Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*
Journal of Semiconductors, 39(8), p.082001_1 - 082001_5, 2018/08
Dynamic nuclear self-polarization (DYNASP) is a phenomenon observed in III-V semiconductors. When electrons of the valence band of a semiconductor are optically excited to the conduction band, a relaxation process of the conduction electrons induces a large nuclear polarization to suddenly occur below a critical temperature. Extending the original theoretical work of Dyakonov et al., we examined the effect of spin distribution of valence electrons excited by the circularly polarized light and the effect of external magnetic field on the phenomenon of the nuclear self-polarization. We found that the nuclear polarization is achieved even above the critical temperatures by the effect of electron polarization and of the external magnetic field. To investigate the phenomenon experimentally, we constructed an apparatus for low-temperature experiments.
Oe, Kazuhiro*; Attallah, M. F.*; Asai, Masato; Goto, Naoya*; Gupta, N. S.*; Haba, Hiromitsu*; Huang, M.*; Kanaya, Jumpei*; Kaneya, Yusuke*; Kasamatsu, Yoshitaka*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1317 - 1320, 2015/02
Times Cited Count：10 Percentile：64.63(Chemistry, Analytical)A new technique for continuous dissolution of nuclear reaction products transported by a gas-jet system was developed for superheavy element (SHE) chemistry. In this technique, a hydrophobic membrane is utilized to separate an aqueous phase from the gas phase. With this technique, the dissolution efficiencies of short-lived radionuclides of 
Mo and 
W were measured. Yields of more than 80% were observed for short-lived radionuclides at aqueous-phase flow rates of 0.1-0.4 mL/s. The gas flow-rate had no influence on the dissolution efficiency within the studied flow range of 1.0-2.0 L/min. These results show that this technique is applicable for on-line chemical studies of SHEs in the liquid phase.
N-labeled nitrogen gas tracer for the imaging of nitrogen fixation in soybean nodulesIshii, Satomi; Igura, Masato*; Yin, Y.-G.; Hung, N. V. P.*; Suzui, Nobuo; Kawachi, Naoki; Koyanagi, Atsushi*; Oyama, Takuji*; Fujimaki, Shu
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 98, 2014/03
partial pressure on nitrogen fixation in soybean plant using positron-emitting tracerHung, N. V. P.; Ishii, Satomi; Suzui, Nobuo; Kawachi, Naoki; Yin, Y.-G.; Koyanagi, Atsushi; Oyama, Takuji*; Fujimaki, Shu
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 99, 2014/03
The impacts of oxygen in rhizosphere on the symbiotic nitrogen fixation in real-time was evaluated under various O partial pressure. Soybean nodules were treated with mixed gas containing N labeled with a radioisotope N and various concentrations of O, and the nitrogen fixation activity in the nodules was visualized by the positron-emitting tracer imaging system (PETIS). The results showed that under normal condition the nitrogen fixation ability of soybean plant was higher compared to that of under the other conditions (0% O and 10% O). There was no significant difference in the nitrogen fixation activity between 0% O and 10% O.
Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*; Nakamura, Shoji
Nuclear Instruments and Methods in Physics Research B, 317(Part B), p.689 - 692, 2013/12
Times Cited Count：1 Percentile：11.54(Instruments & Instrumentation)Dynamic nuclear self-polarization (DYNASP) is a phenomenon that is observed in the III-V semiconductors. When electrons in the valence band of a semiconductor are optically excited to the conduction band, quite large nuclear polarization suddenly occurs below a critical temperature. This phenomenon was theoretically predicted by Dyakonov and Perel. Our recent work predicted that the electrons excited by circularly polarized laser enhance nuclear polarization near the critical temperature. The mechanism of such a large nuclear polarization would be useful for measurements of nuclear magnetic moments of unstable nuclides. However, the experiment on DYNASP can be found only in a conference report. In order to confirm the phenomenon, we have started the study of DYNASP. Preparation of experiments on DYNASP is in progress. In this paper, we describe the present status of the study of nuclear polarization by using DYNASP from the theoretical and experimental aspects.
N as a tracerHung, N. V. P.*; Watanabe, Shiori*; Ishikawa, Shinji*; Otake, Norikuni*; Sueyoshi, Kuni*; Sato, Takashi*; Ishii, Satomi; Fujimaki, Shu; Oyama, Takuji*
Soil Science and Plant Nutrition, 59(6), p.888 - 895, 2013/12
Times Cited Count：4 Percentile：14.01(Plant Sciences)Cm + 
O reactionMurakami, Masashi*; Goto, Shinichi*; Murayama, Hirofumi*; Kojima, Takayuki*; Kudo, Hisaaki*; Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Kudo, Yuki*; Sumita, Takayuki*; et al.
Physical Review C, 88(2), p.024618_1 - 024618_8, 2013/08
Times Cited Count：15 Percentile：66.57(Physics, Nuclear)Production cross sections of Rf isotopes in the Cm + O reaction were measured at the beam energy range of 88.2 to 101.3 MeV by use of a gas-filled recoil ion separator. The excitation functions of 
Rf, 
Rf, and 
Rf were obtained together with those of spontaneously fissioning nuclides which have few-second half-lives and have been assigned to 
Rf and a longer-lived state of Rf. The excitation function of few-second spontaneously fissioning nuclide exhibited the maximum cross section at the O beam energy of 94.8 MeV. The shape of the excitation function was almost the same as that of Rf, whereas it was quite different from those of Rf and Rf. A few-second spontaneously fissioning nuclide previously reported as Rf and Rf observed inCm + O reaction was identified as Rf.
Oyama, Takuji; Fujikake, Hiroyuki*; Yashima, Hiroyuki*; Tanabata, Sayuri*; Ishikawa, Shinji*; Sato, Takashi*; Nishiwaki, Toshikazu*; Otake, Norikuni*; Sueyoshi, Kuni*; Ishii, Satomi; et al.
Soybean Physiology and Biochemistry, p.333 - 364, 2011/11
no abstracts in English
Ishii, Yasuo; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Li, Z.*; Nagame, Yuichiro; Miyashita, Sunao*; Mori, Tomotaka*; Suganuma, Hideo*; Haba, Hiromitsu*; et al.
Bulletin of the Chemical Society of Japan, 84(9), p.903 - 911, 2011/09
Times Cited Count：17 Percentile：49.33(Chemistry, Multidisciplinary)The cation-exchange behavior of element 104, rutherfordium (Rf), was investigated together with its lighter group-4 homologues Zr and Hf, and the tetravalent pseudo-homologue Th in HF/HNO
mixed solution. The results demonstrate that distribution coefficients (
) of Rf in HF/0.10 M HNO decrease with increasing concentration of the fluoride ion [F
], indicating the consecutive formation of fluorido complexes of Rf. We also measured the values of Rf and the homologues as a function of the hydrogen ion concentration [H
]. The log values decrease linearly with an increase of log [H] with slopes between -2.1 and -2.5. This indicates that these elements are likely to form the same chemical compounds: mixture of [MF]
and [MF]
(M = Rf, Zr, Hf and Th) in the studied solution. It is also ascertained that sequence in the fluoride complex formation is Zr 
Hf 
Rf Th.
LaBr(Ce) spectrometer for neutron capture cross section measurementsGoto, Jun*; Harada, Hideo; Kitatani, Fumito; Nagai, Yasuki; Oshima, Masumi; Segawa, Mariko; Toh, Yosuke
Journal of the Korean Physical Society, 59(2), p.1585 - 1588, 2011/08
Times Cited Count：2 Percentile：20.16(Physics, Multidisciplinary)A 4 LaBr(Ce) spectrometer was designed for the measurements of neutron capture cross sections using a prompt -ray spectroscopic method with a time-of-flight technique. An optimum configuration for the 4 LaBr(Ce) spectrometer was adopted from four possible configurations based on comparison of simulated performance and cost of construction. Further simulations were performed to demonstrate performance of the 4 LaBr(Ce) spectrometer.
Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*
Journal of Applied Physics, 110(1), p.013911_1 - 013911_8, 2011/07
Times Cited Count：2 Percentile：9.73(Physics, Applied)Lattice nuclei of III-V type semiconductors can be self-polarized through the contact hyperfine interaction with optically excited electrons on the conduction band at low temperatures. The effect of electrons excited with circularly polarized light is introduced to the theoretical prediction of self-polarization. We found that the degree of nuclear polarization is enhanced in comparison with the use of un-polarized light. The direction of the nuclear polarization is controlled by the orientation of the electron polarization. A hysteresis phenomenon appears in the nuclear polarization when varying the degree of electron polarization.
Ito, Sayuri; Fujimaki, Shu; Kato, Taichi*; Otake, Norikuni*; Sueyoshi, Kuni*; Oyama, Takuji*
Nitrogen assimilation in plants, p.205 - 214, 2010/07
Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Tsukada, Kazuaki; Asai, Masato; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; Sch
del, M.; et al.
Journal of Nuclear and Radiochemical Sciences, 11(1), p.7 - 11, 2010/06
The extraction behavior of rutherfordium (Rf) into trioctylphosphine oxide (TOPO) from 2.0 - 7.0 M HCl solution was studied together with that of the homologues Zr and Hf. The extracted yields of Rf, Zr, and Hf increased with an increase of HCl concentration, and the sequence of their extraction was Zr Hf 
Rf. It is suggested that the stability of the RfCl
2(TOPO) complex is lower than that of the corresponding species of the homologues.
Fujimaki, Shu; Ishii, Satomi; Oyama, Takuji*
Hoshasen To Sangyo, (124), p.32 - 35, 2009/12
The nodule is a symbiotic organ developed on roots of leguminous plants which have been infected with rhizobia, a group of soil bacteria. The plants with nodules can obtain nitrogen nutrition as ammonia converted from nitrogen gas in the air by rhizobia in the nodules. This function, "symbiotic nitrogen fixation", plays a fundamental role in the food production in the world. Recently, we reported that we have successfully visualized the symbiotic nitrogen fixation in soybean plants non-invasively using a positron-emitting tracer imaging system (PETIS) and nitrogen-13-labelled nitrogen gas tracer. In this article, this study is described with the scientific and social backgrounds.
N-labeled nitrogen gas tracer and the imaging of nitrogen fixation in soybean nodulesIshii, Satomi; Suzui, Nobuo; Ito, Sayuri; Ishioka, Noriko; Kawachi, Naoki; Matsuhashi, Shimpei; Otake, Norikuni*; Oyama, Takuji*; Fujimaki, Shu
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 106, 2009/12
