All issues
Volume 39, Issue 8
Displaying 1-4 of 4 articles from this issue
- |<
- <
- 1
- >
- >|
-
Shin-ichi KAMOSHIDA, Hirokazu KAWASE, Yoriyoshi YAMAGUCHI, Shinichi HY ...1996 Volume 39 Issue 8 Pages 377-382
Published: August 20, 1996
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSSeveral Borosilicate glass tubes in which Ne gas had been sealed were maintained at either room or liquid nitrogen temperature for a long period, i.e., 10-70 days. Thermal desorption measurements were carried out using a quadrupole mass spectrometer to determine the amount of Ne atoms absorbed in the tube walls during gas sealing. In the case of samples kept at room temperature, with prolongation of the gas sealing period, desorption peaks shifted to higher temperature and the total amount of absorbed Ne increased, as expected from diffusion theory. In the case of samples kept at liquid nitrogen temperature, however, their thermal desorption behavior was markedly different; although the amount of desorption was much smaller than that for the room-temperature samples, the desorption-peak temperature was apparently unaffected by the sealing period. This indicates that most of the penetrating Ne atoms were trapped within a certain limited range of depth from the Ne-exposed glass surface. The results support the view that atoms with extremely low energy (on the order of meV) can move within a solid over a considerable distance (on an atomic scale), unlike in ordinary thermal diffusion.View full abstractDownload PDF (795K) -
Tadao KANEKO, Takashi IWASAKI, Mieko SAKURAI1996 Volume 39 Issue 8 Pages 383-388
Published: August 20, 1996
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSIn preparation for the fabrication of porous thin-film TiO2 semiconductors, the microstructure and morphology of titanium films deposited under higher Ar gas pressures than usual were observed. Black titanium films were deposited at a pressure of around 12 Pa on stainless steel wires and Cu thin plates, although glossy films were obtained at lower pressures. The black titanium films had a larger apparent thickness than the glossy films. Scanning electron microscopic observation of the films showed that the black films have an extremely porous structure, consisting of separated columns with periodic steps on the lateral surfaces. This morphology indicates that the nuclei formed on the substrate grow periodically to form steps due to the shadowing effect. The surface areas of the black films on the Cu thin plates varied with bias potential. A small negative bias was found to be effective for increasing the surface area of black titanium films. These results suggest that porous TiO2 films can be prepared by applying a suitable oxidation process to the black titanium film which consists of separated columns.View full abstractDownload PDF (2068K) -
Tatsuo ASAMAKI, Katsumi MORO, Akira YAMAGUCHI1996 Volume 39 Issue 8 Pages 389-393
Published: August 20, 1996
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSA nude type magnetron gauge has been developed, which is highly simplified and small. The gauge has only a cathode which is comprised of a thin vacuum chamber containing a magnet, and magnetic pole pieces.
The characteristics of the gauge are investigated in the pressure range of 10-110-8 Pa. Current I vs pressure P in a log-log plot has good linearity. This linearity is sensitive to the distance between cathode and vacuum chamber as an anode d. In the case of a short d of 10mm, the gauge shows good linearity in a wide pressure range of 6 decades, or 10-110-6Pa, with 2 kV of voltage applied to the cathode. This pressure range is very wide compared with that of a conventional penning discharge gauge. In the case of a long d of 19.5 mm, 5 decades, or 10-110-5 Pa, at 3 or 4 kV. With increase or decrease of the applied voltage, the range of linearity will be narrowed. The optimum applied voltages are 2 kV at d-10 mm, and 34 kV at d= 19.5 mm.
It is found that the gauge shows a sudden change of several times in discharge current at a pressure Pc, when the pres-sure is decreased or increased. Pc is 10-510-6 Pa for d = 19.5 mm with an applied voltage of 1.56.0 kV, and 10-310-6 Pa for d = 10 mm with an applied voltage of 1.56.0 kV.
This gauge is very useful for application in rocket and balloon experiments, and for pressure measurement in the deep portion of a vacuum chamber.View full abstractDownload PDF (566K) -
Tatsuo ASAMAKI, Kiyomi OHNUKI, Yoshitaka MIYAJIMA1996 Volume 39 Issue 8 Pages 394-397
Published: August 20, 1996
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSA nude type inverted magnetron gauge which consists of an anode, pole pieces, and a cathode with a thin vacuum chamber containing a magnet is developed. Relatively good uniformity of the magnetic flux density in the central space of the cathode is obtained. The discharge current vs pressure characteristics are measured over a wide pressure range of 10-8 to 10-2 Pa. It is found that the gauge shows good linearity in the discharge current vs pressure plot in the range 10-8 to 10-2 Pa. However, the characteristic curves typically show an abrupt change of slope at 10-5 Pa. Sudden change in the discharge current, as found for a planar magnetron or a cylindrical magnetron with a magnet inside the cathode, is not observed when the pressure is varied.View full abstractDownload PDF (618K)
- |<
- <
- 1
- >
- >|