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JAEA Reports

Vacuum operation test for optical window protective shutters of JT-60SA diagnostic port-plugs

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.

Journal Articles

Meeting report; 18th Plasma Seminar for young researchers

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.

Journal Articles

Signal evaluations using singular value decomposition for Thomson scattering diagnostics

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:1 Percentile:92.51(Instruments & Instrumentation)

Journal Articles

An Optical design and accuracy estimation for a JT-60SA edge Thomson scattering diagnostic

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:1 Percentile:91.29(Instruments & Instrumentation)

Journal Articles

Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system

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:2 Percentile:84.62(Instruments & Instrumentation)

Journal Articles

Anisotropic electron temperature measurements without knowing the spectral transmissivity for a JT-60SA Thomson scattering diagnostic

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:100(Instruments & Instrumentation)

Journal Articles

Principle of an in-situ relative calibration method using a double-pass beam for Thomson scattering diagnostics

Tojo, Hiroshi; Hatae, Takaki; Itami, Kiyoshi

Journal of Instrumentation (Internet), 7(5), p.C05004_1 - C05004_11, 2012/05

 Times Cited Count:10 Percentile:48.68(Instruments & Instrumentation)

Journal Articles

Demonstration of in-situ relative calibration method for a Thomson scattering diagnostic on TST-2

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:79.2(Instruments & Instrumentation)

Journal Articles

First measurement of electron temperature from signal ratios in a double-pass Thomson scattering system

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:10 Percentile:48.68(Instruments & Instrumentation)

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, 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:142 Percentile:0.63(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 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 $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

An ${it in-situ}$ relative calibration method for Thomson scattering diagnostics using a double-pass scattering system

Tojo, 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 ($$T_{rm e}$$): thereby making evaluation of $$T_{rm e}$$ 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.

Journal Articles

Design of collection optics and polychromators for a JT-60SA Thomson scattering system

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:9 Percentile:53.84(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.

Journal Articles

Conceptual design of polychromator for Thomson scattering system in JT-60SA

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 $$gamma$$-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 $$T_{rm e}$$ $$>$$ 10 keV, the time evolution of the averaged relative errors for the radiation resistance fibers increase from 3$$sim$$5% by $$sim 1%$$. However, for the used fibers in JT-60U, the errors are 7$$sim$$8% and they reaches more than 10% in some high $$T_{rm e}$$ conditions, suggesting some difficulties in the measurements.

Journal Articles

Crystal structure and lattice vibration of proton dissolved BaZr$$_{0.8}$$Sc$$_{0.2}$$O$$_{2.9}$$

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:5 Percentile:71.84(Chemistry, Physical)

The neutron diffraction of BaZr$$_{0.8}$$Sc$$_{0.2}$$O$$_{2.9}$$ with and without proton were measured and analyzed by Rietveld method and Maximum Entropy Method. We found that the location of proton is 12${it h}$ 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.

Oral presentation

Change in the crystal structure and lattice vibration by proton dissolution to BaZr$$_{0.8}$$Sc$$_{0.2}$$O$$_{2.9}$$

Shimoyama, Tomotaka*; Tojo, Takeo*; Kawaji, Hitoshi*; Atake, Toru*; Fukazawa, Hiroshi; Igawa, Naoki

no journal, , 

Sc doped BaZrO$$_{3}$$ is one of the canditated materials for solid state proton conductors in the middle temeprature range because of its high proton conducticivity and excellent chemical stability under the humidity. This presentation makes discusion on the crystal structure of BaZr$$_{0.8}$$Sc$$_{0.2}$$O$$_{2.9}$$ with D$$_{2}$$O using Rietveld method and Maximum Entropy method.

Oral presentation

Location of proton and structural relaxation in a perovskite-type proton conductor

Shimoyama, Tomotaka*; Tojo, Takeo*; Kawaji, Hitoshi*; Atake, Toru*; Fukazawa, Hiroshi; Igawa, Naoki

no journal, , 

Proton conductor BaZr$$_{0.8}$$Sc$$_{0.2}$$O$$_{2.9}$$ was synthesized by a solid state reaction method. Neutron diffraction experiments were performed for dried and D$$_{2}$$O dissolute samples at 10 K. The observed data were analyzed by Rietveld method and Maximum Entropy method. It has been clarified that the deuterium exits at 12${it h}$ site. It is founded that the distance between oxide ion site and deuterium site is shorter than the normal distance of O-D.

Oral presentation

Applications of the phase conjugate mirror to Thomson scattering diagnostics

Hatae, Takaki; Yamada, Ichihiro*; Yoshida, Hidetsugu*; Narihara, Kazumichi*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Funaba, Hisamichi*; Minami, Takashi*; Kajita, Shin*; Tojo, Hiroshi; et al.

no journal, , 

no abstracts in English

Oral presentation

Design of collection optics and port-plug for Thomson scattering system in JT-60SA

Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Shinohara, Koji; Itami, Kiyoshi; Aida, Yoshiaki*; Suito, Satoshi*; Fujie, Daijiro*

no journal, , 

Conceptual designs of the collection optics for JT-60SA Thomson scattering have been done. Adapting four glass materials of the lenses used for the collection optics enables to correct the chromatic aberrations with good resolution ($$>$$ 1 mm). The whole radial profile can be measured using three designed collection optics in Port-P1, P2 and P5. The collection optics will be installed in port-plugs accessing from the cryostat to vacuum vessel. In a disruption with a decrease of the plasma current by a time scale of 5 MA/8 ms, the eddy current ($$sim$$0.1 MA/m$$^{2}$$) is strongly generated in the area of 500 mm from the edge of the port-plug with the thickness of 30 mm. Even if the thickness is reduced to 20 mm decreasing the current in the area, the maximum principal stress is still under the limit value for the design.

Oral presentation

Application of SBS phase conjugate mirror to fusion plasma diagnostics

Hatae, Takaki; Kitamura, Shigeru; Sakuma, Takeshi; Hamano, Takashi; Tojo, Hiroshi; Yoshida, Hidetsugu*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Narihara, Kazumichi*; Yamada, Ichihiro*; et al.

no journal, , 

Oral presentation

In-situ relative calibration method for a JT-60SA Thomson scattering measurement

Tojo, Hiroshi; Hatae, Takaki; Itami, Kiyoshi

no journal, , 

no abstracts in English

39 (Records 1-20 displayed on this page)