Vacuum chamber made of soft magnetic material with high permeability

Kamiya, J.; Ogiwara, Norio; Nishikawa, Masaaki; Hikichi, Yusuke; Yanagibashi, Toru; Kinsho, Michikazu

doi:10.1016/j.vacuum.2012.10.007

Cited by 11 publications

(3 citation statements)

References 2 publications

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“…3,11,12 They were generally more than 2 orders of magnitude lower than values reported previously for untreated mild steels and ferritic steels, and slightly lower than that of copper-plated (100 lm) mild steel. 13 The outgassing rates were lower than that of untreated…”

Section: 7-10mentioning

confidence: 61%

“…5,12,41 In these applications, use of low-outgassing low-carbon steels could eliminate the need to coat the inner surface of the material with protective film. However, the steels need appropriate surface coating on the air side, for example, Ni-plating or Teflon coating with which a continuous in situ bakeout is possible up to 250 C. When these steels are used, the inside of the steel chamber should be kept in vacuum, because the steel is susceptible to oxidation during contact with ambient air, and oxidation must be avoided.…”

Section: Methodsmentioning

confidence: 99%

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Thermal outgassing rates of low-carbon steels

Park¹,

Ha²,

Cho

2015

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

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Outgassing rates of three low-carbon steels were measured using rate-of-rise and throughput methods. Outgassing rates of water vapor during pump-down were higher than those of stainless steels, probably due to the nature of native surface oxide layer. However, hydrogen outgassing rates without a high temperature pretreatment were as low as (1–4) × 10−10 Pa m3 s−1 m−2, which is much lower than that of untreated stainless steels. No dramatic reduction was observed in H2 outgassing after vacuum annealing at 850 °C for 12 h, suggesting that the low-carbon steels had been fully degassed during the steelmaking processes. This may be due to the use of the Ruhrstahl-Hausen vacuum process during steel refining instead of an older process, such as argon-oxygen decarburization. The extremely low H2 outgassing rate from low-carbon steels makes them applicable for use in ultrahigh vacuum or even extreme high vacuum applications, particularly where magnetic field shielding is needed.

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Section: 7-10mentioning

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Thermal outgassing rates of low-carbon steels

Park¹,

Ha²,

Cho

2015

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

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“…1,4,5 Furthermore, choosing the ideal material for a specific vacuum application is critical; for example, selecting a ferritic material with a very low outgassing rate for use in magnetic field shielding. 6,7 During such investigations, precise measurement of the outgassing rate is a prerequisite for the screening of candidate materials or verifying the effectiveness of various pretreatment procedures. 8,9 The most common experimental techniques used for the measurement of outgassing are the throughput and rate-of-pressure rise methods.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Outgassing Rates of Steels

Park

Kim

et al. 2016

JoVE

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Steels are commonly used materials in the fabrication of vacuum systems because of their good mechanical, corrosion, and vacuum properties. A variety of steels meet the criterion of low outgassing required for high or ultrahigh vacuum applications. However, a given material can present different outgassing rates depending on its manufacturing process or the various pretreatment processes involved during the fabrication. Thus, the measurement of outgassing rates is highly desirable for a specific vacuum application. For this reason, the rate-of-pressure rise (RoR) method is often used to measure the outgassing of hydrogen after bakeout. In this article, a detailed description of the design and execution of the experimental protocol involved in the RoR method is provided. The RoR method uses a spinning rotor gauge to minimize errors that stem from outgassing or the pumping action of a vacuum gauge. The outgassing rates of two ordinary steels (stainless steel and mild steel) were measured. The measurements were made before and after the heat pretreatment of the steels. The heat pretreatment of steels was performed to reduce the outgassing. Extremely low rates of outgassing (on the order of 10 Pa m sec m) can be routinely measured using relatively small samples.

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