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Zn
Y
alloy using X-ray photoelectron spectroscopyMiyazaki, Hidetoshi*; Akatsuka, Tatsuyoshi*; Kimura, Koji*; Egusa, Daisuke*; Sato, Yohei*; Itakura, Mitsuhiro; Takagi, Yasumasa*; Yasui, Akira*; Ozawa, Kenichi*; Mase, Kazuhiko*; et al.
Materials Transactions, 64(6), p.1194 - 1198, 2023/06
Times Cited Count：1 Percentile：54.26(Materials Science, Multidisciplinary)We investigated the electronic structure of the MgZnY alloy using hard and soft X-ray photoemission spectroscopy and electronic band structure calculations to understand the mechanism of the phase stability of this material. Electronic structure of the MgZnY alloy showed a semi-metallic electronic structure with a pseudo-gap at the Fermi level. The observed electronic structure of the MgZnY alloy suggests that the presence of a pseudogap structure is responsible for phase stability.
Sato, Yohei*; Egusa, Daisuke*; Miyazaki, Hidetoshi*; Kimura, Koji*; Itakura, Mitsuhiro; Terauchi, Masami*; Abe, Eiji*
Materials Transactions, 64(5), p.950 - 954, 2023/05
Times Cited Count：1 Percentile：54.26(Materials Science, Multidisciplinary)Dilute Mg-Zn-Y alloy with a mille-feuille structure (MFS) exhibits a mechanical strength comparable to Mg-Zn-Y alloy with long period stacking/ordered (LPSO) structure through kink deformation. In order to deepen understanding the thermal stability of the MFS-type Mg alloys, it is required to clarify the solute cluster structures composed of Zn and Y in solute enriched stacking faults (SESFs). In this study, electron energy-loss and energy dispersive X-ray spectroscopy based on scanning transmission electron microscopy (STEM-EELS/EDS) were conducted to investigate the electronic structure and composition of Zn and Y in the SESFs of the MFS-Mg alloy. Zn-L2,3 spectra indicated that the valence charges of Zn in the dilute Mg alloy were different from that of the LPSO-type Mg-Zn-Y alloy. In addition, the intensity ratio of L3/L2 in Y-L2,3 spectrum of the dilute MFS-Mg alloy was larger than that of the LPSO-Mg alloy, reflecting the electron occupancies of 4d3/2 and 4d5/2 orbitals of Y atoms were different from those of the LPSO-Mg alloys. STEM-EELS analysis of the SESF composition in the dilute MFS-Mg alloy indicated that the Zn/Y ratio should be lower than that of the LPSO-Mg alloy, which was confirmed also by STEM-EDS measurements. These results indicate that the cluster structure in the SESFs of the dilute MFS-Mg alloy should be different from the ideal Zn6Y8 cluster in the LPSO-type Mg-Zn-Y alloys.
LiIshiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Jung, H. S.*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.
Nuclear Instruments and Methods in Physics Research B, 376, p.379 - 381, 2016/06
Times Cited Count：8 Percentile：60.26(Instruments & Instrumentation)Okazaki, Hiro; Sumi, Mika; Sato, Mitsuhiro; Kayano, Masashi; Kageyama, Tomio; Martinez, P.*; Xu, N.*; Thomas, M.*; Porterfield, D.*; Colletti, L.*; et al.
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/01
The quality control section of Plutonium Fuel Development Center (PFDC) in Japan Atomic Energy Agency has been analyzing isotopic compositions and content of plutonium and uranium as well as impurity and physics of nuclear materials in the process of MOX fuel fabrication for accountancy purpose as well as process control purposes. These analytical techniques are also effective for nuclear forensics to identify the source, history, and route of the material by determining a composition and chemical property of it. Therefore, PFDC cooperates with Los Alamos National Laboratory which has broad experience and established measurement skill for nuclear forensics, and evaluates the each method, procedure, and analytical data toward R&D of characterizing a nuclear fuel for forensics purposes. This paper describes the approaches to develop characterization techniques of nuclear fuel for nuclear forensic purpose at PFDC.
Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masaaki; Oda, Yoshihiro; Saito, Tatsuo; Kato, Tomoko; Niizato, Tadafumi; Iijima, Kazuki; Sato, Haruo; Yui, Mikazu; et al.
Nuclear Science and Engineering, 179(1), p.104 - 118, 2015/01
Times Cited Count：8 Percentile：56.13(Nuclear Science & Technology)The prediction of the distribution and fate of radioactive materials eventually deposited at surface in the Fukushima area is one of the main objectives and expected to be achieved in an efficient manner. In order to make such prediction, a number of mathematical models of radioactive contaminants, with particular attention on cesium, on the land and in rivers, lakes, and estuaries in the Fukushima area are developed. Simulation results are examined with the field investigations simultaneously implemented. The basic studies of the adsorption/absorption mechanism of cesium and soils have been performed to shed light on estimating distribution coefficient between dissolved contaminant and particulate contaminant.
Li tracerIshiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Katayama, Ichiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.
Japanese Journal of Applied Physics, 53(11), p.110303_1 - 110303_4, 2014/11
Times Cited Count：4 Percentile：18.17(Physics, Applied)Okazaki, Hiro; Sumi, Mika; Abe, Katsuo; Sato, Mitsuhiro; Kageyama, Tomio
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10
The quality control section of Plutonium Fuel Development Center (PFDC) has been analyzing isotopic compositions by Mass Spectrometry as well as content by Isotope Dilution Mass Spectrometry (IDMS) of plutonium and uranium in nuclear materials. Along with establishing and managing the quality assurance system, ensuring the reliability of the analysis data is important. PFDC has been establishing the quality management system with ISO 9001. We addressed technical improvement to improve further reliability of analysis quality, and accredited for ISO/IEC 17025 in March 2010. While ISO 9001 consists of management requirements for quality system of organizations, ISO/IEC 17025 consists of technical requirements for the competence of testing and calibration laboratories in addition to the management requirements. In this presentation, we report our approaches to have accreditation and operation status for isotopic compositions and content of plutonium and uranium in nuclear materials.
Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Sato, Takahiro; Kamiya, Tomihiro; Fukuda, Mitsuhiro*; Yokota, Wataru
Nuclear Instruments and Methods in Physics Research B, 306, p.40 - 43, 2013/07
Times Cited Count：2 Percentile：19.73(Instruments & Instrumentation)no abstracts in English
mixed gasIshiyama, Hironobu*; Yamaguchi, Kanako*; Mizoi, Yutaka*; Watanabe, Yutaka*; Das, S. K.*; Hashimoto, Takashi*; Miyatake, Hiroari*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Oyaizu, Mitsuhiro*; et al.
Journal of Instrumentation (Internet), 7(3), p.C03036_1 - C03036_14, 2012/03
Times Cited Count：8 Percentile：37.67(Instruments & Instrumentation)We developed an active-target type gas counter operating with low He/CO (10%) detector gas for application in studying low-energy nuclear reactions using radioactive beams. A 400-
m-thick gas electron multiplier (THGEM) was used as the proportional counter for high injection rate capability. We examined the gas gain stability and the influence of ion feedback on particle tracks at high beam injection rates of up to 10
particles per second (pps) using a low-energy 
C beam. From the result of this examination, we found that the THGEM was found to be applicable for our active target at high injection rates of up to 10 pps.
Kamiya, Tomihiro; Takano, Katsuyoshi; Sato, Takahiro; Ishii, Yasuyuki; Nishikawa, Hiroyuki*; Seki, Shu*; Sugimoto, Masaki; Okumura, Susumu; Fukuda, Mitsuhiro*
Nuclear Instruments and Methods in Physics Research B, 269(20), p.2184 - 2188, 2011/10
Times Cited Count：15 Percentile：73.97(Instruments & Instrumentation)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.
Kurashima, Satoshi; Yoshida, Kenichi; Oikawa, Masakazu*; Sato, Takahiro; Miyawaki, Nobumasa; Yuyama, Takahiro; Okumura, Susumu; Kashiwagi, Hirotsugu; Ishibori, Ikuo; Nara, Takayuki; et al.
Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2024 - 2027, 2009/06
Times Cited Count：10 Percentile：56.67(Instruments & Instrumentation)A heavy-ion microbeam with energy of hundreds of MeV is utilized for research in biotechnology and materials science at the JAEA AVF cyclotron facility. Beam users need microbeams providing a wide range of linear energy transfer (LET). In order to vary LET widely, we have to change the ion species and/or energy. A cocktail beam acceleration technique is frequently used to change the ion species quickly. Ion species and energy can be changed by slightly shifting the acceleration frequency. The cocktail acceleration technique has been applied to microbeam production for quick change of ion species of a microbeam. As a result, we have succeeded to reduce considerably microbeam changing time to within 30 minutes between a 260 MeV Ne and a 520 MeV Ar. No deterioration of a microbeam spot size has been confirmed using a secondary electron microscope image of a copper mesh.
Oikawa, Masakazu*; Sato, Takahiro; Kamiya, Tomihiro; Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro*; Sakai, Takuro; Yokota, Wataru
Applied Radiation and Isotopes, 67(3), p.484 - 487, 2009/03
Times Cited Count：6 Percentile：41.05(Chemistry, Inorganic & Nuclear)no abstracts in English
Kurashima, Satoshi; Miyawaki, Nobumasa; Oikawa, Masakazu*; Sato, Takahiro; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Okumura, Susumu; Fukuda, Mitsuhiro*; Kamiya, Tomihiro; Yokota, Wataru
JAEA-Conf 2008-012, p.48 - 50, 2009/03
no abstracts in English
Iba, Katsuyuki*; Ozeki, Takahisa; Totsuka, Toshiyuki; Suzuki, Yoshio; Oshima, Takayuki; Sakata, Shinya; Sato, Minoru; Suzuki, Mitsuhiro; Hamamatsu, Kiyotaka; Kiyono, Kimihiro
Fusion Engineering and Design, 83(2-3), p.495 - 497, 2008/04
Times Cited Count：4 Percentile：29.49(Nuclear Science & Technology)Fusion research grid is an environment of collaborative researches using a network that connects scientists far apart and let them collaborate effectively over the difference in time and distance in a nuclear fusion research. Fundamental technology of Fusion research grid has been developed at JAEA in the VizGrid project under the e-Japan project at Ministry of Education, Culture, Sports, Science and Technology (MEXT). Remote research environments of experiments, diagnostics, analyses and communications were developed on Fusion research grid. We have developed prototype systems that include a remote experiment system, a remote diagnostics system, and a remote analysis system. All users can access these systems from anywhere because Fusion research grid does not required closed network like Super SINet to maintain security. The prototype systems were verified in experiments at JT-60U and their availability was confirmed.
Imai, Nobuaki*; Jeong, S.-C.*; Oyaizu, Mitsuhiro*; Arai, Shigeaki*; Fuchi, Yoshihide*; Hirayama, Yoshikazu*; Ishiyama, Hironobu*; Miyatake, Hiroari; Tanaka, Masahiko*; Okada, Masayuki*; et al.
Review of Scientific Instruments, 79(2), p.02A906_1 - 02A906_3, 2008/02
Times Cited Count：13 Percentile：51.72(Instruments & Instrumentation)KEKCB is an 18 GHz Electron Cyclotron Resonance (ECR) ion source and is a charge breeder device for converting mass-separated 1
radioactive ions to multi-ionized ones by utilizing an axial injection technique to the ECR plasma. It is a part of the Tokai Radioactive Ion Accelerator Complex (TRIAC) facility. Based on the developments so far, converting efficiencies for metal elements, such as barium and indium, and for gaseous elements, such as krypton and xenon, are improved to be 7 
and 2 , respectively. And it is confirmed that the efficiency is nearly the constant for short-lived (t
1 sec) isotopes. Background ions mixed in the output beams are supressed to be 600 pps from 10
pps by applying all aluminum electrodes and high pressure pure-water cleanings.
Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Oikawa, Masakazu*; Yoshida, Kenichi; Kamiya, Tomihiro; Fukuda, Mitsuhiro*; Sato, Takahiro; Nara, Takayuki; Agematsu, Takashi; et al.
Nuclear Instruments and Methods in Physics Research B, 260(1), p.65 - 70, 2007/07
Times Cited Count：10 Percentile：59.1(Instruments & Instrumentation)no abstracts in English
Oikawa, Masakazu*; Sato, Takahiro; Sakai, Takuro; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Kurashima, Satoshi; Okumura, Susumu; Fukuda, Mitsuhiro*; Yokota, Wataru; Kamiya, Tomihiro
Nuclear Instruments and Methods in Physics Research B, 260(1), p.85 - 90, 2007/07
Times Cited Count：41 Percentile：92.3(Instruments & Instrumentation)A high-energy heavy ion microbeam system has been developed in an ion accelerator facility, TIARA of JAEA Takasaki. This was the first trial to focus heavy ion beams with an energy range of a few tens MeV/n from an AVF cyclotron accelerator in the world. The focusing system equipped with a quadruplet quadrupole magnet lens, multi beam collimators and beam scanners has been optimized following almost the same way as that of previously developed microbeam system in TIARA. However the ion beams from the cyclotron accelerator has a larger energy variation 
E/E and also has a larger beam current instability I/I than those of electro-static machine in general. We had to overcome these biggest problems in microbeam forming. This paper will outline the new focusing system we have developed in TIARA, and show the results of 1 m resolution by secondary electron mapping method and of single ion hit experiment for the track detectors and semiconductor test devices.
Yokota, Wataru; Sato, Takahiro; Oikawa, Masakazu*; Sakai, Takuro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Kamiya, Tomihiro; Fukuda, Mitsuhiro*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 185, 2007/02
The paper reports the progress in the development of the focusing microbeam formation technique in fiscal 2005, which is under way at the TIARA for application to research fields of biotechnology and semiconductor for space use. A 2-m-diameter microbeam was successfully attained using 260 MeV-
Ne
in fiscal 2004. The 1.7-m diameters on average were obtained at several experiments in the following fiscal year. This suggested that the microbeams might be usable for a several-hour experiment. The irradiation in the atmosphere was therefore tested for the first time. Furtheremore, a method to reduce an effect of vibration of apparatuses on the beam size was discussed, because 0.6-m amplitude in vibtation of the focusing lens was observed with a laser displacement sensor.
Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Ishibori, Ikuo; Yoshida, Kenichi; Sato, Takahiro; Kashiwagi, Hirotsugu; Yuri, Yosuke; Agematsu, Takashi; Nara, Takayuki; et al.
Proceedings of 18th International Conference on Cyclotrons and Their Applications (CYCLOTRONS 2007), p.131 - 133, 2007/00
We have been improving the beam quality of the JAEA (Japan Atomic Energy Agency) AVF cyclotron to form a several-hundred-MeV heavy-ion microbeam by a magnetic focusing lens. An energy spread 
of the order of 10
, obtained by ordinary acceleration using a fundamental dee voltage, makes it difficult to focus an ion beam to a spot size of 1 m in diameter with focusing lens because of the chromatic aberration. A flat-top acceleration system using the fifth-harmonic frequency of the acceleration frequency was installed in the cyclotron in order to reduce to the order of 10
. In addition, developments of a new center region, an energy spread measurement system using an analyzing magnet and a high performance beam buncher are in progress. The energy spread of the 260 MeV Ne beam has been reduced to 0.05% by the flat-top acceleration, and the microbeam with a spot size of approximately 1 m has been successfully formed.
