Achieving ultrahigh vacuum in an unbaked chamber with glow discharge conditioning
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- 作者：ZIAUDDIN KHAN ; PRATIBHA SEMWAL ; KALPESH R DHANANI ; DILIP C RAVAL…
- 关键词：Ultrahigh vacuum ; glow discharge conditioning ; hydrogen ; helium
- 刊名：Pramana
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：88
- 期：1
- 全文大小：
- 刊物类别：Physics and Astronomy
- 刊物主题：Physics, general; Astronomy, Observations and Techniques; Astrophysics and Astroparticles;
- 出版者：Springer India
- ISSN：0973-7111
- 卷排序：88
文摘
Glow discharge conditioning (GDC) has long been accepted as one of the basic wall conditioning techniques for achieving ultrahigh vacuum in an unbaked chamber. As a part of this fundamental experimental study, a test chamber has been fabricated from stainless steel 304 L with its inner surface electropolished on which a detailed investigation has been carried out. Both helium and hydrogen gases have been employed as discharge cleaning medium. The discharge cleaning was carried out at 0.1 A /m2 current density with working pressure maintained at 1.0 × 10 -2 mbar. It was experimentally observed that the pump-down time to attain the base pressure ~10 -8 mbar was reduced by 62% compared to the unbaked chamber being pumped to this ultimate vacuum. The results were similar irrespective of whether the discharge cleaning medium is either hydrogen or helium. It was also experimentally established that a better ultimate vacuum could be achieved as compared to theoretically calculated ultimate vacuum with the help of discharge cleaning.