Journal of the Vacuum Society of Japan
Online ISSN : 1882-4749
Print ISSN : 1882-2398
ISSN-L : 1882-2398
Volume 57, Issue 4
Displaying 1-12 of 12 articles from this issue
Special Issue: 54th Vacuum Symposium Proceedings (1) (Tsukuba, 2013)
Letter
  • Atsushi SUZUKI, Hisao HOJO, Takichi KOBAYASHI
    2014 Volume 57 Issue 4 Pages 125-127
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      The influence of atmospheric humidity on the output of a quartz friction pressure gauge (Q-gauge) was investigated because the viscosity and molecular weight of water, which is the source of humidity, are significantly smaller than those of air; therefore, they affect the Q-gauge output. In the temperature range of 10-50℃, the nominal pressure from the Q-gauge decreased by approximately several percent owing to relative humidity, which was higher than the lower explosive limit of hydrogen, and this may cause an error in hydrogen sensing. The Q-gauge output was pressure-calibrated using its humidity dependence, and therefore, the difference in the pressure-calibrated Q-gauge output (Q-gauge ratio) between 0 and 100% humidity was reduced to 1% of the Q-gauge ratio. It was indicated that the influence of humidity can be excluded by calibrating the Q-gauge output using the humidity dependence necessary for the outdoor use of that type of hydrogen sensor.
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  • Yasuhito GOTOH, Yoshiki YASUTOMO, Hiroshi TSUJI
    2014 Volume 57 Issue 4 Pages 128-130
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      Electron emission characteristics of field emitter arrays with hafnium nitride cathode were investigated at the low temperature of 140 K. The characteristics at 140 K showed little difference from those at room temperature immediately after cooling down. After a long term operation, the collector current showed a gradual dicrease. The reason for the decrease would be due to the adsorption of the residual gas molecules onto the emitter surface, which raised the work function of the emitter surface. Detailed analysis with an aid of Seppen-Katamuki analysis revealed that the decrease of the collector current during the long term operation was attibuted to the decrease in the number of the active tips: contribution of the emission from the emitters with higher work function became negligible to those with lower work function.
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  • Junichiro KAMIYA, Michikazu KINSHO, Naoki HAYASHI, Hideaki HOTCHI, Nor ...
    2014 Volume 57 Issue 4 Pages 131-135
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      In J-PARC 3GeV synchrotron (RCS), new quadrupole magnets (quadrupole correctors) are planned to be installed in order to correct the edge focusing effect and tune. In this report, we describe a deliberation flow about the design of the beam ducts, which is installed in the quadrupole corrector. The effects of eddy current were examined in the case of the titanium duct. The calculated results showed that the temperature rise was too much (up to over 350℃) and the magnetic field in the beam duct is largely distorted. Therefore we decided to employ an alumina ceramics beam duct. The stress and displacement, which are caused by the atmospheric pressure, were estimated by simulating the realistic equipments in the beam line. It was found that there was no large stress and displacement by installing the alumina ceramics duct.
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  • Kyo SHIBATA, Yusuke SUETSUGU, Ken-ichi KANAZAWA, Takuya ISHIBASHI, Hir ...
    2014 Volume 57 Issue 4 Pages 136-139
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      SuperKEKB, which is an upgrade of the KEKB B-factory (KEKB), is a next-generation high-luminosity electron-positron collider. The construction started on July 2010, and is still underway. In order to achieve its extra high performance (about 40 times the luminosity of the KEKB), many upgrades of the vacuum system must be performed. More than 1200 beam pipes are being replaced with new one with antechambers. To deal with a serious electron cloud issue expected in a positron ring, several types of countermeasures are adopted such as a titanium nitride (TiN) coating, solenoid field, clearing electrode and groove structure. More than 920 beam pipes had been delivered, and the pre-baking and TiN coating of them are finished in KEK so far. About 500 beam pipes are already installed in the SuperKEKB and the construction work of the vacuum system will be completed by the end of 2014.
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  • Kazue TAKAHASHI
    2014 Volume 57 Issue 4 Pages 140-143
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      Removal of small glass spheres on a Si substrate by using adhesion forces between particles and dielectric films was investigated. An upper Si electrode and a dielectric film such as that of polyethylene or polyvinylchloride were placed on a lower Si electrode to which small glass spheres were adhered, and a high voltage was applied to the two Si electrodes for 60 s. The glass spheres had a diameter of 2-20 μm and were adhered to the dielectric film; about 40-50% of the spheres were removed from the Si substrate in the first iteration of a removal process. The removal process was repeated several times, and a high removal rate of about 80% was obtained after the fifth iteration. This implies that the largest glass spheres were removed in the first iteration, and smaller ones were removed in subsequent iterations. The dependence of the particle removal rate on the particle size was evaluated as the ratio of the adhesive force between the particle and film and that between the particle and substrate. Further, it was found that the particle size decreases with the removal rate. This result was in agreement with the experimental result.
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  • Daiki EDAMOTO, Kazuki HAYAHISA, Motochika OKANO, Naoya TSUBOI, Tomonor ...
    2014 Volume 57 Issue 4 Pages 144-146
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      We investigated the effect of ion-beam irradiation on the growth of graphene at the 3C-SiC(111)/SiO2/Si(111) substrate by the surface decomposition method. When Ar+ ions with 1 keV were irradiated to the sample surface for 1 h and then annealed at 1200℃ for 1 min, graphene layers were formed. The graphene surfaces were evaluated by scanning tunneling microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. We found that the growth of graphene at the surface decomposition method is promoted by ion-beam irradiation. This result indicated that ion-beam irradiation caused breakage of Si-C bonds and induced desorption of Si atoms from the surface.
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  • Yuuko FUKAZAWA, Suguru SHIBATA, Masatake IKEMOTO, Hiroki KAWATOKO, Yas ...
    2014 Volume 57 Issue 4 Pages 147-151
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      Growth forms of Au particles prepared by vacuum evaporation methods on KBr(001) and KCl(001) substrates with two types of surface steps prepared by thermal sublimation and by electron stimulated desorption are studied by using a carbon backing method with a transmission electron microscope. Spiral steps of monoatomic height have been prepared on the substrate surfaces by heat sublimation. Epitaxial Au particles with pyramidal shapes and other multiply twined particles are grown by the vacuum evaporation on the substrates at temperatures of 50-450℃. The size distributions of the particles on the substrates are reported and the typical size is measured to be smaller than 20×20 nm2. The ratio of populations of the multiply twined particles along the KBr steps is increased compared with that on the flat area. However, this increase in the ratio is not observed for particles grown on KCl. Additionally, step assemblies are prepared by electron stimulated desorption (ESD). The dependence of the size distributions of the Au particles grown on the substrates on electron fluence is measured for the ESD surfaces. With increasing electron fluence, the peak particle distribution size becomes smaller and particles smaller than 1 nm are observed.
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  • Takeo NAKANO, Ryo YAMAZAKI, Shigeru BABA
    2014 Volume 57 Issue 4 Pages 152-154
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      The transport process of sputtered atoms has been studied experimentally through deposition rate measurement by changing the target-to-substrate (T-S) distance systematically along with the gas pressure and target element. The deposition rate showed power-law decay with the T-S distance, and the slope of the log-log plot became steep at a transition pressure. The transition pressure decreased as the mass of the sputtered atoms decreased, which suggested that the transition was related to the transport of the sputtered atoms and their thermalization. Two separated thickness monitors showed that the thickness uniformity was worsened by the thermalization.
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  • Taisuke NAKAYAMA, Yuji SUGA, Kazuki NAGATOMO, Tomonori IKARI, Masamich ...
    2014 Volume 57 Issue 4 Pages 155-158
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      We have investigated the generation of spherical carbon particles, using the columnar type plasmas excited vertically at the pressure of 1×10−1 Pa composed of CH4-Ar mixed gas. It is found that the spherical carbon particles of micrometer sizes grow in the plasma sheath only when Si(100) substrate temperature and contents of CH4 are near 1066 K and near 18%, respectively. The result of high resolution SEM and high resolution TEM observations strongly suggest the growth of elementary particles of ca. 10 nm which including carbon onions of ca. 2-4 nm in the plasma.
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  • Satoshi KATANO, Yousoo KIM, Toshikazu KITAGAWA, Maki KAWAI
    2014 Volume 57 Issue 4 Pages 159-162
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      We have studied the adsorption of molecular tripods, having a Br atom (BATT) and a ferrocene derivative (Ferrocene-ATT) at the head position of the adamantane-based trithiolate, on Au(111) using scanning tunneling microscopy (STM). BATT forms well-ordered self-assembled monolayer (SAM), of which the structure is same as that of Ferrocene-ATT. This indicates that the functional unit connected to the head part of the adamantane-based trithiolate does not affect the molecular ordering of SAMs. The electronic structures of individual adamantane-based molecular tripods were evaluated using scanning tunneling spectroscopy (STS). While the STS spectrum of BATT has almost no feature at near the Fermi level, the electronic state, i.e., highest occupied molecular orbital (HOMO), of Ferrocene-ATT, was clearly observed in the same spectrum range when taken at the well-ordered SAM. STS mapping revealed the distribution of the HOMO state of Ferrocene-ATT, which indicates the rotational motion of the ferrocene unit.
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  • Hiroyuki YOSHIKI, Yoshiki OTOSAKA
    2014 Volume 57 Issue 4 Pages 163-166
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      TiO2 has a photocatalytic function when irradiated with ultraviolet (UV) light. One of photochemical reaction on a TiO2 surface is the photo-induced redox reactions of adsorbed substances, and the other is the photo-induced high hydrophilicity. It is expected, therefore, that a UV transparent glass tube having a TiO2 coated inner wall shows the self-cleaning and hydrophilic properties. TiO2 coating on an inner wall of a narrow (φ2.5 mm) quartz glass tube by an atmospheric-pressure RF (13.56 MHz, 12 W) plasma using titanium tetraisopropoxide (TTIP) as a precursor and a carrier gas He is studied. RF driven parallel-plate electrodes are closely attached on the outer surface of a glass tube to generate He glow plasma inside the tube. It revealed that O2 addition of 2% or more to the TTIP/He gas is key to prepare a pure TiO2, otherwise TiC is mixed among the deposited TiO2 films. The tube inner wall was covered with TiO2 films of 500-900 nm in a thickness after a TTIP/O2(2%)/He plasma treatment for 20 min. TiO2 microparticles with 1-4 μm in a diameter also deposited on an inner wall under the electrodes and the number of microparticles increased with increasing a gas flow rate. It seems that these microparticles are charged negatively and, therefore, are attracted toward the electrodes.
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  • Takashi MIURA
    2014 Volume 57 Issue 4 Pages 167-170
    Published: 2014
    Released on J-STAGE: April 30, 2014
    JOURNAL FREE ACCESS
      We developed an experimental setup to measure in real time the charge generated during friction between a metal and a plastic material in a vacuum chamber in order to reveal the absolute quantity of the initial charge separation in a vacuum and the relaxation processes, e.g., micro-gap discharge, in a gas ambience. In this paper, the static electricity generated by friction between stainless steel or gold metal and polyethylene terephthalate (PET) was measured. The density of the separated charge on the PET-rubbed surface was evaluated. The two-dimensional spatial distribution of light emission from the gas discharge was recorded with a CCD camera, and the voltage of the discharge was estimated.
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