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Volume 35, Issue 6
Displaying 1-7 of 7 articles from this issue
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Tomoaki HINO, Masao HASHIBA, Yuko HIROHATA, Kotaro ISHIO, Toshiro YAMA ...1992 Volume 35 Issue 6 Pages 553-558
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSBoron-doped graphite and a-C/B : H film are regarded as attractive low Z plasma facing materials, since radiation loss due to oxygen and carbon impurities is largely reduced. It is also suggested that the radiation enhanced sublimation (RES) might be reduced by the boron doping. However, suitable temperature range for this material has not yet been clarified. From the oxidation experiments of the boron-doped graphite, it is observed that B2O3 formed by oxygen gettering evaporates at the temperature over 900°C. From the measurement of RES, it is also shown that the boron evaporation becomes dominant when the temperature exceeds approximately 1000°C. In addition, the reduction of the RES yield is not clearly observed in our experiment. Thus it is proposed that the suitable temperature range of boron-doped graphite should be less than about 900°C. The boron-doped graphite can be used only for walls of relatively low temperature, i.e., the first wall region. To extend this material to the divertor region of the fusion experimental reactor such as ITER, the heat flux must be greatly reduced by expanding the divertor configuration.View full abstractDownload PDF (887K) -
Yasushi MAKABE, Yuko HIROHATA, Tomoaki HINO, Toshiro YAMASHINA1992 Volume 35 Issue 6 Pages 559-566
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSThe structure of Mo films prepared under different deposition conditions was examined in terms of surface morphology (SEM), effective surface area (SRF) and crystallization (XRD). In addition, the spatial distribution of excited species of Mo was measured by optical emission spectroscopy (OES). As the Ar gas pressure increased, the surface roughness of film was enhanced. In addition, the crystallization deteriorated. It was observed that the emission of Mo from plasma sharply decreased around the substrate when the pressure was relatively high. It was presumed that the distribution of the incident angle of Mo particle on the substrate became isotropic at high pressure due to collision with Ar atoms. It was concluded that the surface roughness was enhanced by the collision of sputtered Mo atom with Ar atom.View full abstractDownload PDF (968K) -
Kenji OHARA, Ichiro ANDO, Nagamitsu YOSHIMURA1992 Volume 35 Issue 6 Pages 567-573
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSPumping characteristics of sputter ion pumps with anode-cells of φ 17 mm, φ 24 mm and φ 29 mm, were measured for N2 with three magnetic fields (i.e., 0.15 T, 0.2 T and 0.3 T at the center of the discharge area) in an ultrahigh vacuum range between 1 × 10-8 Pa and 1 × 10-6 Pa. The pumping speed of the pump with φ17 mm cells increased significantly with increasing magnetic fields. However, the pump with φ 17 mm cells and a magnetic field of 0.3 T exhibited negligible pumping speed at pressures <1.5 × 10-8 Pa. The pump with φ 24 mm cells and a magnetic field of 0.3 T showed a fairly high pumping speed in the range between 1 × 10-8 Pa and 1 ×10-6 Pa. The pump with φ 29 mm cells and 0.3 T showed the highest pumping speed at pressures <2 × 10-8 Pa, although its pumping speed in the 10-7 Pa range were comparatively low.View full abstractDownload PDF (1132K) -
Nagamitsu YOSHIMURA, Kenji OHARA, Ichiro ANDO, Haruo HIRANO1992 Volume 35 Issue 6 Pages 574-578
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSAr-pumping characteristics of diode-type sputter ion pumps with various shapes of “Ta/Ti” cathode-pairs were measured by an orifice method. Every pump had 30 anode cells (φ 24 mm, 28 mm in length) and 0.15 T of magnetic flux density at the center of the discharge area. The Ar-pumping speed of the pump of a “flat Ta/flat Ti” cathode-pair was about 13 l/s in the 10-5 Pa range. On the other hand, the Ar-pumping speeds of the pumps of a “holed Ta on flat Ti/flat Ti” cathode pair and of a “slotted Ta on flat Ti/flat Ti” pair were both about 23 l/s in the 10-5 Pa range. The pump of a “slotted Ta on flat Ti/slotted Ti on flat Ti” pair showed the Ar-pumping speed as 2425 l/s, which was a slightly higher than the speed of the pump of the “slotted Ta on flat Ti/flat Ti” pair. The N2-pumping speed of the pump of the “slotted Ta on flat Ti/flat Ti” pair was measured as about 50 l/s in the 10-6 Pa range and about 55 l/s in the 10-5 Pa range. Therefore, the Ar-pumping speed was as high as 42% of the N2-pumping speed for the pump of a “slotted Ta on flat Ti/flat Ti” cathode-pair.View full abstractDownload PDF (682K) -
Hiromi HISAMATSU, Takashi MOMOSE, Hajime ISHIMARU1992 Volume 35 Issue 6 Pages 579-582
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDownload PDF (678K) -
[in Japanese]1992 Volume 35 Issue 6 Pages 583-587
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDownload PDF (1154K) -
Masahiro TOSA, Kazuhiro YOSHIHARA1992 Volume 35 Issue 6 Pages 588-593
Published: June 20, 1992
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDownload PDF (774K)
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