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Matsueda, Makoto; Kawakami, Tomohiko*; Koarai, Kazuma; Terashima, Motoki; Fujiwara, Kenso; Iijima, Kazuki; Furukawa, Makoto*; Takagai, Yoshitaka*
Chemistry Letters, 51(7), p.678 - 682, 2022/07
Times Cited Count:6 Percentile:58.73(Chemistry, Multidisciplinary)New methodology for a simultaneous isotope speciation of various Pu isotopes without complicated isobaric interferences is developed by using inductively coupled plasma-mass spectrometry (ICP-MS). In analyzing ICP tandem MS (ICP-MS/MS), CO gas reactions in a dynamic reaction cell (DRC) almost eliminated the background noise intensity produced by isobaric interference from isotopes originating from actinides such as Am, Cm, and U at the locations (m/z) of significant Pu isotopes (Pu, Pu, Pu, Pu, Pu).
Dohi, Terumi; Omura, Yoshihito*; Yoshimura, Kazuya; Sasaki, Takayuki*; Fujiwara, Kenso; Kanaizuka, Seiichi*; Nakama, Shigeo; Iijima, Kazuki
PLOS ONE (Internet), 16(5), p.e0251828_1 - e0251828_16, 2021/05
Times Cited Count:6 Percentile:40.04(Multidisciplinary Sciences)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count:44 Percentile:97.1(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Sasaki, Takayuki*; Matoba, Daisuke*; Dohi, Terumi; Fujiwara, Kenso; Kobayashi, Taishi*; Iijima, Kazuki
Journal of Radioanalytical and Nuclear Chemistry, 326(1), p.303 - 314, 2020/10
Times Cited Count:3 Percentile:34.82(Chemistry, Analytical)Nishimori, Nobuyuki; Nagai, Ryoji; Matsuba, Shunya; Hajima, Ryoichi; Yamamoto, Masahiro*; Miyajima, Tsukasa*; Honda, Yosuke*; Uchiyama, Takashi*; Iijima, Hokuto*; Kuriki, Masao*; et al.
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.174 - 178, 2014/06
no abstracts in English
Nagao, Seiya*; Niibori, Yuichi*; Tanaka, Tadao; Sasaki, Takayuki*; Saito, Takumi*; Kirishima, Akira*; Yoshikawa, Hideki; Iijima, Kazuki; Hama, Katsuhiro; Iwatsuki, Teruki; et al.
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 20(1), p.3 - 14, 2013/06
This paper shows a current status of groundwater colloids studies on the performance assessment of geological disposal of radioactive wastes in Japan, and summaries realistic approach of the colloids studies at a substantial research network for Japanese universities and institutes.
Yamamoto, Masahiro*; Uchiyama, Takashi*; Miyajima, Tsukasa*; Honda, Yosuke*; Sato, Kotaro*; Matsuba, Shunya*; Saito, Yoshio*; Kobayashi, Masanori*; Kurisu, Hiriki*; Hajima, Ryoichi; et al.
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.717 - 720, 2010/08
A 500-kV photocathode DC electron gun which can supply the beam of a low emittance and a high average current has been developed in collaboration with KEK, JAEA, Hiroshima Univ., Nagoya Univ. and Yamaguchi Univ. The vacuum of the gun chamber has to be lower Extreme High Vacuum for maintain cathode-life time. A titanium chamber and new material of ceramic were employed to reduce outgassing rate. The result of outgassing rate of the gun chamber is described in this report.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Uchiyama, Takashi*; Kobayashi, Masanori*; Muto, Toshiya*; Matsuba, Shunya*; Sakanaka, Shogo*; Sato, Kotaro*; Saito, Yoshio*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.860 - 862, 2009/08
A newly 500 kV electron gun (2nd - 500 kV gun) for an ERL light source is designed at KEK. A new concept and state of-the-art technologies of vacuum system, ceramic insulators, high voltage power supply, photocathode and preparation system will be employed. The details are described in this report.
Iwatsuki, Teruki; Sato, Haruo; Tanai, Kenji; Inagaki, Manabu; Sawada, Atsushi; Niinuma, Hiroaki; Ishii, Eiichi; Maekawa, Keisuke; Tomura, Goji; Sanada, Hiroyuki; et al.
JAEA-Research 2009-002, 156 Pages, 2009/05
The research and development plan for geological investigation, engineering technology and safety assessment during the drilling of a shaft down to intermediate depth are summarized according to the Midterm Plan till 2009 Fiscal year of JAEA. This report describes subject, current status and programme in the "Phase 2: Construction phase" (investigations during construction of the underground facilities). Furthermore regarding R&D plan in next Midterm Plan of JAEA, preliminary ideas are summarized.
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Ando, Masaki; Iijima, Susumu*; Oigawa, Hiroyuki; Sakurai, Takeshi; Nemoto, Tatsuo*; Okajima, Shigeaki; Osugi, Toshitaka*; Ono, Akio; Hayasaka, Katsuhisa; Sodeyama, Hiroshi
JAEA-Data/Code 2006-006, 67 Pages, 2006/03
As a part of research and development of an advanced fueled fast reactor, we carried out benchmark experiments in the FCA-XVII-1 core with MOX simulating fuel to obtain reference data to be compared with those measured in the FCA-XVI-1 and XVI-2 cores simulating metallic fueled FBR. Following nuclear characteristics were measured in the experiments: Criticality, reaction rate ratio, sample reactivity worth, sodium void reactivity effect and U Doppler effect. Extra measurements were performed in modified FCA-XVII-1 cores to obtain experimental data for various reactor types: (1) Measurement of sodium void reactivity effect in various plutonium isotope compositions, (2) Measurement of sodium void reactivity effect in a core where axial blanket was replaced with a sodium layer and (3) Measurement of various nuclear characteristics in a nitride fuel region. This report describes methods and results of the above experiments and method of analysis.
Ijima, Takashi; Irie, Tsutomu
Saikuru Kiko Giho, (28), p.67 - 69, 2005/09
ACROSS (Accurately Controlled Routinely Operated Signal System) is a method to investigate any change of physical state in the Earth's interior using accurately controlled seismic ans/or electromagnetic sources. We preliminary obtained Pg, Sg, and possible plate boundary reflected PxP phase using one-moth long stacking data up to nearly 70 km distance. The seismic reflection experiment across the central Japan revealed the strong PxP reflection phase from 30-40 km deep of the Philippine Sea Plate boundary around the Tokai Region, Japan (Iidaka et al., 2003). The same seismic exploration line crossed the area where many active faults distribute. One of the big issues for revealing the loading process for active faults is to examine the process in the lower crust around active faults. To examine the seismic exploration records obtained by Iidaka et al. (2003), we noticed the presence of strong phases, which can be explained as PxP reflection from the plane at 20 km deep around the Atera fault, which is one of the most active faults in Japan. The phases are identified by a number of explosions on the survey line from north to south of this region. One of high possibilities for the 20km reflector is the detachment in the lower crust. The high velocity contrast can explain such PxP reflection phase. We evaluated the possibility to observe such phase by the ACROSS transmission from the present source located in Toki city and may conclude to be able to observe such phase and its temporal change, if the seismometers are placed 50-100km distance north of this region. We also generated synthetic seismograms to confirm the detection. In addition to seismic ACROSS, electrometric ACROSS method may identify the strong-reflection source and its temporal change using resistively analysis around the Tokai Region, Japan. This approach can give high possibility to watch the change of physical state beneath the active faults and it may contribute for the earthquake forecasting.
Ijima, Takashi; Kiyota, Shiko; Miyamoto, Hisami; KANEHIRA, Yoshiki
JNC TN4410 2004-008, 49 Pages, 2004/10
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Ijima, Takashi; Matsushima, Akira; MORITA, Satoshi; Hochin, Koji
JNC TN4410 2004-004, 46 Pages, 2004/03
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; Iijima, Takashi;
Journal of Nuclear Science and Technology, 41(2), p.183 - 195, 2004/02
Times Cited Count:10 Percentile:55.63(Nuclear Science & Technology)None
Otani, Tsukasa; Iijima, Takashi; Shiratori, Yoshitake
Journal of Nuclear Science and Technology, 40(11), p.959 - 969, 2003/11
Times Cited Count:5 Percentile:36.77(Nuclear Science & Technology)None
Ijima, Takashi;
JNC TN3410 2002-005, 52 Pages, 2003/03
Iijima, Takashi; ;
Chikyu Kankyo To Shingata Genshiryoku Puranto Ni Kansuru Kokusai Kaigi (GENES4/ANP2003), 0 Pages, 2003/00
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