著者

秋道 斉

出版者

一般社団法人 日本真空学会

雑誌

Journal of the Vacuum Society of Japan (ISSN:18822398)

巻号頁・発行日

vol.56, no.6, pp.220-226, 2013 (Released:2013-06-28)

参考文献数

17

被引用文献数

1 8

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In this text, fundamentals of vacuum measurement are reviewed focused on the operation principles of common (both total and partial) pressure gauges. Total pressure gauges are classified into three categories. The first category includes e.g. U-tube, McLeod, diaphragm and bourdon gauges, which directly measure the actual “pressure” of gases. The second consists of Pirani, thermocouple, thermistor, spinning rotor and quartz gauges, which utilize the transport phenomena of rarefied gases. And the third comprises Penning, cold cathode magnetron, Bayard-Alpert and extractor gauges, which makes use of the ionization phenomena in gases. Partial pressure gages, also known as mass spectrometers, can also be classified into three categories which discriminate the mass of gas molecules 1) electrically, 2) electro-magnetically and 3) by time-of-flight, respectively. In this text, quadrupole mass spectrometer (category 1) and magnetic deflection mass spectrometer (category 2) are discussed in some detail.

著者

吉田 肇 城 真範 平田 正紘 秋道 斉

出版者

The Vacuum Society of Japan

雑誌

真空 (ISSN:18822398)

巻号頁・発行日

vol.54, no.5, pp.298-306, 2011-05-20

被引用文献数

3

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A transmission probability <i>W</i> of gas molecules passing through a vacuum component is usually calculated using the Monte Carlo method. In the calculation, it is generally assumed that gas molecules are introduced to a smooth surface and scatter with cosine low. Since the <i>W</i> is influenced by the shape and/or roughness of the surface in practice, the precise calculation of <i>W</i> requires the inclusion of surface geometry. The conventional Monte Carlo method, however, needs very long time to calculate the <i>W</i> for a cylinder with many corrugations, in other words, rough surface. In this paper, a new method to decrease the time for a calculation with rough surface is described. In the new method, the scattering angle distribution distorted by corrugations is analytically calculated. The distorted distribution is used to determine the scattering angle of the gas molecules at the surface. In the case of a cylinder with the ratio of length to the radius <i>L/r</i> of 5, the ratio of the <i>W</i> with V-shaped corrugations to that without corrugations is 0.77 at minimum. Results of the calculation were obtained by both the new method and the conventional method, and are identical within 0.5%. The time required by the new method was more than 100 times shorter than that by the conventional one.<br>