Measurement system for low outgassing materials by switching between two pumping paths

Saito, Kazuya; Sato, Yukie; Inayoshi, Sakae; Tsukahara, Sonoko

doi:10.1016/0042-207x(96)00149-2

Cited by 17 publications

(11 citation statements)

References 3 publications

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“…The distribution of hydrogen atoms around the surface layer was analyzed by a time of flight -secondary ion mass spectrometry (TOF-SIMS). The outgassing rate was estimated by a modified orifice method switching between two pumping paths (SPP) [17]. The detection limit of the system was 7×10 -13 Pams -1 since the upstream and downstream pressures attained to 10 -9 Pa and below, the orifice conductance C 0 was set to 6.1x10 -3 m 3 s -1 and the sample area was 8.9×10 -1 m 2 [13].…”

Section: Surface Finishingmentioning

confidence: 99%

Application of titanium materials to vacuum chambers and components

Kurisu

Ishizawa

Yamamoto

et al. 2008

J. Phys.: Conf. Ser.

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This paper describes the outgassing properties of titanium materials, and development of vacuum chambers and components for practical UHV/XHV systems. The mechano-chemically polished and the chemically polished titanium materials have a smooth surface and a thin (≤ 10 nm) oxide surface layer, which showed extremely low outgassing rate below 10-12 Pams-1 after baking process. In order to fabricate practical vacuum systems welding, metallizing and brazing processes were optimized, and complex shaped vacuum chambers and various vacuum components such as a bellows, valve, electric feedthrough and ceramic duct with titanium sleeve were fabricated. Sufficient mechanical properties and durability were obtained for practical use.

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Section: Surface Finishingmentioning

confidence: 99%

Application of titanium materials to vacuum chambers and components

Kurisu

Ishizawa

Yamamoto

et al. 2008

J. Phys.: Conf. Ser.

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“…The two-path method is described in Ref. 7. It also has the advantage that the x-ray limit and outgassing rate of the gauge are canceled out by the difference method used.…”

Section: Two-path Methodsmentioning

confidence: 99%

“…The two-path method can be used to measure very low outgassing rates, for example, with an orifice conductance of 6ϫ10 Ϫ3 m 3 s Ϫ1 the lowest outgassing rate measurable by the two-path method has been shown to be less than 10 Ϫ11 Pa m s Ϫ1 ; this is a factor of about 100 less than that of the conventional throughput method. 7…”

Section: Outgassing Ratementioning

confidence: 99%

Recommended practices for measuring and reporting outgassing data

Redhead

2002

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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This document recommends a set of uniform procedures for the reporting of outgassing data. Its intention is to establish a consistent set of units, nomenclature, methods of data presentation, and certain experimental parameters in order that outgassing data from different sources is consistently reported so as to be useful to all. This document was prepared by a subcommittee of the Recommend Practices Committee of the American Vacuum Society and is an updating of a previous Recommended Practice published in 1965.

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“…where M is the AMU of the gas, T is the temperature in K, P " is the pressure in the main chamber in Torr, and A is the area of the main chamber in cm. Modulating the conductance from the sample chamber to the pumping chamber has been used to compensate for chamber wall effects [4]. From Moraw [5] the sticking fraction, s, can be determined by changing the conductance between two known conductances, G 1 and G 2 , measuring the pressure on the vessel side where the sample is located, p "1 and p "2 , and on the pumping side p p1 and p p2 for the two cases.…”

Section: Rga Analysismentioning

confidence: 99%

High temperature outgassing tests on materials used in the DIII-D tokamak

Holtrop

Hansink

2006

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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This paper is a continuation of previous work on determining the outgassing characteristics of materials used in the DIII-D magnetic fusion tokamak [K.L. Holtrop, J. Vac. Sci. Technol. A 17, 2064 (1999)]. Achievement of high performance plasma discharges in the DIII-D tokamak requires careful control of impurity levels. Among the techniques used to control impurities are routine bakes of the vacuum vessel to an average temperature of 350 o C. Materials used in DIII-D must not release any impurities at this temperature that could be transferred to the first wall materials and later contaminate plasma discharges. To better study the behavior of materials proposed for use in DIII-D at elevated temperatures the initial outgassing test chamber was improved to include an independent heating control of the sample and a simple load-lock chamber. The goal was to determine not only the total degassing rate of the material during baking but to also determine the gas species composition and to obtain a quantitative estimate of the degassing rate of each species by the use of a Residual Gas Analyzer. Initial results for aluminum anodized using three different processes, stainless steel plated with black oxide and black chrome, and a commercially available fiber optic feedthrough will be presented.

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Measurement system for low outgassing materials by switching between two pumping paths

Cited by 17 publications

References 3 publications

Application of titanium materials to vacuum chambers and components

Application of titanium materials to vacuum chambers and components

Recommended practices for measuring and reporting outgassing data

High temperature outgassing tests on materials used in the DIII-D tokamak

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