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Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count：13 Percentile：98.52(Quantum Science & Technology)Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11
Times Cited Count：3 Percentile：85.06(Physics, Atomic, Molecular & Chemical)Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12
Times Cited Count：7 Percentile：89.76(Physics, Atomic, Molecular & Chemical)Fujita, Hiroki; Nojima, Takehiro; Nagaoka, Mika; Osawa, Takahito; Yokoyama, Hiroya; Ono, Hironobu*
KEK Proceedings 2016-8, p.168 - 172, 2016/10
An automatic analysis system was developed to analyze Strontium-90 (
Sr) radioactivity in environmental sample for 2013-2015. Various kinds of ashed environmental samples were used in performance tests of the automatic system. These tests were successful without any system trouble. However, Sr concentration had not been measured using the samples analyzed by the system. In this research, Sr concentration in seaweed sample was compared by between the system's analysis and worker's one. Moreover, the system was improved in each analysis process.
Si with XPS and XASEsaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki
Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07
Times Cited Count：16 Percentile：39.25(Chemistry, Physical)XPS is widely used for non-destructive chemical state analysis of solid materials. In this method, depth profiling can be carried out by a combination with ion beam sputtering. However, the sputtering often causes segregation and preferential sputtering of atoms and gives inaccurate information. The use of energy-tunable X-rays from synchrotron radiation (SR) enables us to perform non-destructive depth profiling in XPS. Here, the analytical depth can be changed by changing excitation X-ray energy. In the present study, we examined methods to perform depth profiling with XPS by changing excitation energy and XAS by changing electron energy for detection. These methods were then applied to the analysis of native surface oxide layers on MgSi crystals. In this XAS analysis, the peak at 1843.4 eV becomes dominant when the electron energy for detection increases, which implies that Si-O or Si-O-Mg structure is formed as the surface oxide layer on the MgSi.
Imazawa, Ryota; Kawano, Yasunori; Ono, Takehiro; Itami, Kiyoshi
Review of Scientific Instruments, 87(1), p.013503_1 - 013503_7, 2016/01
Times Cited Count：5 Percentile：25.19(Instruments & Instrumentation)no abstracts in English
Nojima, Takehiro; Fujita, Hiroki; Nagaoka, Mika; Osawa, Takahito; Yokoyama, Hiroya; Ono, Hironobu*
KEK Proceedings 2015-4, p.111 - 115, 2015/11
Automatic strontium-90 analysis system was developed for environmental sample in this research. The system was successful to do wet ashing, chemical separation and ion exchange processes using robot, automatic heating system and so on. Hand-made control program can operate the system by itself.
Hatae, Takaki; Yatsuka, Eiichi; Hayashi, Toshimitsu; Yoshida, Hidetsugu*; Ono, Takehiro; Kusama, Yoshinori
Review of Scientific Instruments, 83(10), p.10E344_1 - 10E344_3, 2012/10
Times Cited Count：15 Percentile：55.18(Instruments & Instrumentation)A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz).
Imazawa, Ryota; Kawano, Yasunori; Ono, Takehiro; Kusama, Yoshinori
Plasma and Fusion Research (Internet), 6(Sp.1), p.2402032_1 - 2402032_5, 2011/08
This paper describes results from the first integrated analysis on the feasibility of a retro-reflector (RR) installed in the ITER vacuum vessel. We make thermal and structural analyses of passively-cooled RR and terrace retro-reflector array (TERRA) by using heat load conditions on ITER. In the case of RR, the temperature reaches over 600
C, and the flatness of deformed mirror surface forming RR is approximately 80 
m. Although the maximal displacement of mirror surface is large, 69% of the incident-laser power returns to a diagnostic room, disturbance of phase is 
and rotation angle of polarization plane is less than 0.06 . On the other hand, the temperature of TERRA is approximately 350C, and the flatness of the deformed mirror surface is less than 10 m. The flatness of the mirror surface of the deformed TERRA is much smaller than laser wavelength (118 m), but the global shape is curved to ruin the coherent phase of laser light. The curvature radius of TERRA is 21 m, and 49% of the incident-laser power returns to the diagnostic room, disturbance of phase is 
, and rotation angle of polarization plane is less than 0.06. Since the optimized incident angles of flat and curved TERRA are different, a real-time feedback control of the incident angle is necessary for applying TERRA to ITER poloidal polarimeter.
Imazawa, Ryota; Kawano, Yasunori; Ono, Takehiro; Kusama, Yoshinori
Review of Scientific Instruments, 82(2), p.023116_1 - 023116_5, 2011/02
Times Cited Count：2 Percentile：12.50(Instruments & Instrumentation)Hatae, Takaki; Hayashi, Toshimitsu; Yatsuka, Eiichi; Kajita, Shin*; Yoshida, Hidetsugu*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Yahagi, Kenichi*; Shinobu, Katsuya*; Ono, Takehiro; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.253 - 258, 2010/08
Okamoto, Masaaki*; Hiraishi, Takehiro*; Ono, Noriyasu*; Takamura, Shuichi*; Nakano, Tomohide; Kawano, Yasunori; Ozeki, Takahisa; Sugihara, Masayoshi
Europhysics Conference Abstracts (CD-ROM), 31F, 4 Pages, 2007/00
It is of importance to evaluate the decay time of the plasma current for estimation of the electromagnetic force acting on the vacuum vessel during plasma disruptions in tokamak devices. The L/R model predicts that the decay time is proportional to three-haves power of the electron temperature, indicating the importance of the electron temperature for the estimation. However, it is difficult to measure the electron temperature of the disruptive plasma with the Langmuir probe due to the heat flux and due to the significant electromagnetic force. We propose a measurement technique of the electron temperature by using temperature-sensitive He I lines with high time resolution. In this method, the incident light to a spectrometer is divided into three, each of which transmits a bandpass filter, and then is measured with an absolutely calibrated photo-multiplier. The measured intensity ratios are analyzed with a collisional-radiative model. It is confirmed that the electron temperature determined by this technique is in agreement with that measured by a Langmuir probe in some devices. In the present work, the temporal evolution of the electron temperature during the disruptive plasma of JT-60U is measured with this technique.
Sakamoto, Shinichi; Meigo, Shinichiro; Konno, Chikara; Kai, Tetsuya; Kasugai, Yoshimi; Harada, Masahide; Fujimori, Hiroshi*; Kaneko, Naokatsu*; Muto, Suguru*; Ono, Takehiro*; et al.
JAERI-Tech 2004-020, 332 Pages, 2004/03
JAERI-Tech-2004-020.pdf:17.93MB
One of the experimental facilities in Japan Proton Accelerator Research Complex (J-PARC) is the Materials and Life Science Experimental Facility (MLF), where high-intensity neutron beams and muon beams are used as powerful probes for materials science, life science and related engineering. The neutrons and muons are generated with high-intensity proton beam from 3-GeV rapid cycling synchrotron (RCS). The high-intensity proton beam has to be effectively transported, and a neutron production target and a muon production target have to be also properly irradiated. The principal design of the 3-GeV proton beam transport facility (3NBT) is systematized.
Sakamoto, Shinichi; Meigo, Shinichiro; Konno, Chikara; Harada, Masahide; Miyake, Yasuhiro*; Kasugai, Yoshimi; Muto, Suguru*; Fujimori, Satoru*; Ono, Takehiro; Ikeda, Yujiro
JAERI-Tech 2001-075, 168 Pages, 2001/12
JAERI-Tech-2001-075.pdf:12.78MB
no abstracts in English
Kawano, Yasunori; Iwamae, Atsushi; Ogawa, Hiroaki; Sugie, Tatsuo; Hatae, Takaki; Yatsuka, Eiichi; Kondoh, Takashi; Ishikawa, Masao; Sato, Kazuyoshi; Hayashi, Toshimitsu; et al.
no journal, ,
no abstracts in English
Kawano, Yasunori; Kondoh, Takashi; Ishikawa, Masao; Hatae, Takaki; Hayashi, Toshimitsu; Ono, Takehiro; Ogawa, Hiroaki; Sugie, Tatsuo; Iwamae, Atsushi; Kusama, Yoshinori; et al.
no journal, ,
Progress in ITER diagnostics development in Japan is presented. (1) Micro Fission Chamber: A bending test of the mineral insulated cable has been carried out since its smallest bending radius would be 12 cm in the vacuum vessel. It has been confirmed that no damage has been observed even at the bending radius is small as 10 cm. (2) Thomson Scattering (Edge): It has been confirmed that the prototype YAG laser amplifier satisfies the target performance of ITER requirement. (3) Poloidal Polarimeter: Study of retro-reflectors in the first wall modules and the divertor cassette has been progressed. (4) Impurity Influx Monitor (Divertor): Mechanical designs of mirror box and optical shutter in the divertor cassette have been designed. (5) Upper Port Plug: For the generic design of the upper port plug (UPP), mesh modeling of UPP has been performed for the E-M analysis. Application of HIP (Hot Isostatic Press) method for manufacturing of UPP has been proposed.
Meigo, Shinichiro; Oi, Motoki; Kai, Tetsuya; Ono, Takehiro; Harada, Masahide; Ikezaki, Kiyomi; Haraguchi, Tetsuya; Akutsu, Atsushi; Fujimori, Hiroshi*; Sakamoto, Shinichi
no journal, ,
no abstracts in English
Meigo, Shinichiro; Fujimori, Hiroshi*; Kai, Tetsuya; Kasugai, Yoshimi; Oi, Motoki; Ono, Takehiro; Ikezaki, Kiyomi; Shinomiya, Kenji; Sakamoto, Shinichi
no journal, ,
no abstracts in English
Hatae, Takaki; Hayashi, Toshimitsu; Kajita, Shin*; Yoshida, Hidetsugu*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Yahagi, Kenichi*; Shinobu, Katsuya*; Ono, Takehiro; Kusama, Yoshinori
no journal, ,
no abstracts in English
Kawano, Yasunori; Ishikawa, Masao; Sato, Kazuyoshi; Kusama, Yoshinori; Hayashi, Toshimitsu; Ono, Takehiro; Ebisawa, Katsuyuki*; Wakabayashi, Kuniaki*; Hiramatsu, Miho*; Kiyohara, Michio*; et al.
no journal, ,
no abstracts in English
