The outgassing rate of a small test chamber made of type 304 stainless steel has been measured as a function of pumping speed in the range from 0.3 to 200 ℓ/s. The chamber was first exposed to air and then pumped with different pumping speeds for three days at 20 °C without baking. Typical outgassing rates of the chamber are determined from the measurement of steady pressures at the pumping time of 72 h. It is found, as a result, that measured outgassing rates q obey a set of power laws of and , where S/A is the ratio of pumping speed S to the surface area A of the chamber, C1 and C2 are constants, the exponents m1 and m2 are 0.8282 for S/A⩾10−3 ℓ/s cm2 and 0.4655 for S/A⩽10−3 ℓ/s cm−2. It is shown that the observed power law can be derived from theoretical consideration and is useful to estimate the ultimate pressure of an unbaked vacuum system.
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March 1997
Research Article|
March 01 1997
Experimental study on the scaling law of the outgassing rate with a pumping parameter
K. Akaishi;
K. Akaishi
National Institute for Fusion Science, Chikusaku, Nagoya 464-01, Japan
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Y. Kubota;
Y. Kubota
National Institute for Fusion Science, Chikusaku, Nagoya 464-01, Japan
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O. Motojima;
O. Motojima
National Institute for Fusion Science, Chikusaku, Nagoya 464-01, Japan
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M. Nakasuga;
M. Nakasuga
Plasma Physics Laboratory, Kyoto University, Uji, Kyoto 611, Japan
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Y. Funato;
Y. Funato
Suzuka Technical College, Suzuka 510-02, Japan
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M. Mushiaki
M. Mushiaki
Kawasaki Medical School, Kurashiki 701-01, Japan
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J. Vac. Sci. Technol. A 15, 258–264 (1997)
Article history
Received:
July 26 1996
Accepted:
November 15 1996
Citation
K. Akaishi, Y. Kubota, O. Motojima, M. Nakasuga, Y. Funato, M. Mushiaki; Experimental study on the scaling law of the outgassing rate with a pumping parameter. J. Vac. Sci. Technol. A 1 March 1997; 15 (2): 258–264. https://doi.org/10.1116/1.580522
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