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Kokusen, Shigeharu; Yoshida, Maiko; Tojo, Hiroshi
JAEA-Technology 2015-041, 26 Pages, 2016/02
JAEA-Technology-2015-041.pdf:8.03MB
Shutters will be installed in front of vacuum windows of some diagnostics in JT-60SA to avoid deposition of impurity onto the vacuum window during wall cleaning and plasma conditioning. Two types of shutter systems had been designed. One has a light shutter (0.5 kg) with rotary motion in vacuum. Another has a heavy shutter (3 kg) with vertical motion in vacuum. For the both types, malfunction due to increase of friction coefficients of the sliding parts in vacuum is concerned. In the present paper, Durability, abrasion and friction coefficient of the sliding parts has been investigated and the shutter designs have been validated. The light shutter with rotary motion successfully rotated required times (4000 times), and the design was validated. On the other hand, for the heavy shutter with vertical motion, the test could not be carried out due to the large friction of the sliding parts. This result suggests that we should change the material of the sliding parts to reduce the friction or change the design from the sliding structure to other ones such as a structure using pulleys and bearings. In the test of the heavy shutter with vertical motion, the friction coefficient increased from 1.3 to 4.5 in the vacuum chamber and from 0.4 to 2.5 in the air.
Fukumoto, Masakatsu; Miyata, Yoshiaki; Tojo, Hiroshi
Purazuma, Kaku Yugo Gakkai-Shi, 91(5), P. 371, 2015/05
"18th Plasma Seminar for young researches" (by Department of Advanced Plasma Research, Sector of Fusion Research and Development, Japan Atomic Energy Agency) was held in Naka Fusion Institute, March 3rd through 6th of 2015. The objective of this seminar is that the young researchers in charge of the future fusion research expand their cross-sectoral network. This seminar was entitled "Crystallization of technology of plasma measurement and control" and we invited the lectures not just for fusion plasma but for technology of plasma measurement and control to study the technology of measurement and control of different fields from their fields. There were 8 invited lectures and 17 public lectures and young researchers had an animated discussion.
Tojo, Hiroshi; Yamada, Ichihiro*; Yasuhara, Ryo*; Yatsuka, Eiichi; Funaba, Hisamichi*; Hatae, Takaki; Hayashi, Hiroshi*; Itami, Kiyoshi
Review of Scientific Instruments, 85(11), p.11D865_1 - 11D865_3, 2014/11
Times Cited Count：2 Percentile：11.13(Instruments & Instrumentation)Tojo, Hiroshi; Hatae, Takaki; Hamano, Takashi; Sakuma, Takeshi; Itami, Kiyoshi
Journal of Instrumentation (Internet), 8(12), p.C12025_1 - C12025_13, 2013/12
Times Cited Count：3 Percentile：17.10(Instruments & Instrumentation)Tojo, Hiroshi; Hatae, Takaki; Hamano, Takashi; Sakuma, Takeshi; Itami, Kiyoshi
Review of Scientific Instruments, 84(9), p.093506_1 - 093506_8, 2013/09
Times Cited Count：3 Percentile：17.10(Instruments & Instrumentation)Tojo, Hiroshi; Hatae, Takaki; Yatsuka, Eiichi; Itami, Kiyoshi
Review of Scientific Instruments, 83(10), p.10E346_1 - 10E346_3, 2012/10
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)Tojo, Hiroshi; Hatae, Takaki; Itami, Kiyoshi
Journal of Instrumentation (Internet), 7(5), p.C05004_1 - C05004_11, 2012/05
Times Cited Count：10 Percentile：43.89(Instruments & Instrumentation)Tojo, Hiroshi; Ejiri, Akira*; Hiratsuka, Junichi*; Yamaguchi, Takashi*; Takase, Yuichi*; Itami, Kiyoshi; Hatae, Takaki
Journal of Instrumentation (Internet), 7(4), p.P04005_1 - P04005_11, 2012/04
Times Cited Count：3 Percentile：17.15(Instruments & Instrumentation)Tojo, Hiroshi; Ejiri, Akira*; Hiratsuka, Junichi*; Yamaguchi, Takashi*; Takase, Yuichi*; Itami, Kiyoshi; Hatae, Takaki
Review of Scientific Instruments, 83(2), p.023507_1 - 023507_4, 2012/02
Times Cited Count：11 Percentile：46.69(Instruments & Instrumentation)
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.42(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
relative calibration method for Thomson scattering diagnostics using a double-pass scattering systemTojo, Hiroshi; Hatae, Takaki; Itami, Kiyoshi
Plasma and Fusion Research (Internet), 6, p.1302018_1 - 1302018_3, 2011/05
A new method of in-situ relative calibration for Thomson scattering diagnostics using a double-pass scattering system is proposed. Ratio of scattered light signals between the first and second pass depend on electron temperature (
): thereby making evaluation of without considering relative transmissivities possible. Determination of relative transmissivities of each spectral channel can be assigned at the same time. Feasibility of the method based on parameters in a JT-60SA Thomson scattering diagnostic is also examined.
Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Itami, Kiyoshi; Aida, Yoshiaki*; Suito, Satoshi*; Fujie, Daijiro*
Review of Scientific Instruments, 81(10), p.10D539_1 - 10D539_3, 2010/10
Times Cited Count：10 Percentile：43.96(Instruments & Instrumentation)Designs of collection optics for JT-60SA Thomson scattering system are presented. By using tangential (to the toroidal direction) YAG laser injection, three collection optics without strong chromatic aberrations generated by the wide viewing angle and small design volume measure almost all the radial space. For the edge plasma measurements, we optimized the channel number and wavelength ranges of band-pass filters in polychromator to reduce relative error in the electron temperature by considering the all spatial channels and double-pass laser system with different geometric parameters.
Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Itami, Kiyoshi
Journal of Plasma and Fusion Research SERIES, Vol.9, p.288 - 293, 2010/08
Significant loss in transmissivity of the used fiber after the 18 years operations in JT-60U are found. Therefore, an optimization of the filter's configuration of the polychromator in Thomson scattering system for the high performance plasmas in JT-60SA is an essential task. Especially, loss in optical components induced by radiation from neutrons and 
-ray should be examined. In this paper, an optimization of the filter configuration in the polychromator is executed and expected error degradation due to the radiation damages in the measurements are also estimated with a comparison between used fibers in JT-60U and radiation resistance fibers. In 
10 keV, the time evolution of the averaged relative errors for the radiation resistance fibers increase from 3
5% by 
. However, for the used fibers in JT-60U, the errors are 78% and they reaches more than 10% in some high conditions, suggesting some difficulties in the measurements.
Sc
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Shimoyama, Tomotaka*; Tojo, Takeo*; Kawaji, Hitoshi*; Atake, Toru*; Fukazawa, Hiroshi; Igawa, Naoki
Solid State Ionics, 180(6-8), p.560 - 562, 2009/05
Times Cited Count：6 Percentile：29.39(Chemistry, Physical)The neutron diffraction of BaZrScO with and without proton were measured and analyzed by Rietveld method and Maximum Entropy Method. We found that the location of proton is 12
site near oxygen ion. The heat capacity of sample with proton is larger than that without proton. This difference is discussed in term of the changes of the crystal structure and lattice vibrations due to the dissolution of proton.
Kawano, Yasunori; Sugie, Tatsuo; Ogawa, Hiroaki; Tojo, Hiroshi; Yatsuka, Eiichi; Imazawa, Ryota; Hatae, Takaki; Hamano, Takashi; Sakuma, Takeshi; Takeuchi, Masaki; et al.
no journal, ,
no abstracts in English
Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Itami, Kiyoshi; Ejiri, Akira*; Hiratsuka, Junichi*; Yamaguchi, Takashi*; Takase, Yuichi*
no journal, ,
no abstracts in English
Hatae, Takaki; Yatsuka, Eiichi; Yoshida, Hidetsugu*; Fujita, Hisanori*; Tsubakimoto, Koji*; Nakatsuka, Masahiro*; Yasuhara, Ryo*; Tojo, Hiroshi; Sakuma, Takeshi
no journal, ,
no abstracts in English
Tojo, Hiroshi; Yamada, Ichihiro*; Yasuhara, Ryo*; Yatsuka, Eiichi; Funaba, Hisamichi*; Hayashi, Hiroshi*; Hatae, Takaki; Itami, Kiyoshi
no journal, ,
no abstracts in English
Kawano, Yasunori; Takeuchi, Masaki; Tojo, Hiroshi; Kitazawa, Sin-iti; Yamamoto, Tsuyoshi; Takeyama, Shigeharu; Yatsuka, Eiichi; Imazawa, Ryota; Sakuma, Takeshi; Shimada, Takahiko; et al.
no journal, ,
no abstracts in English
Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Itami, Kiyoshi
no journal, ,
no abstracts in English
