Reduction of outgassing rate by glow discharge cleaning

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Journal of Vacuum Science Technology A

OSTI ID:801734

Li, Minxu; Dylla, H F

The effectiveness of glow discharge cleaning (GDC) as a means of decreasing the pump-down time of vacuum systems was studied. We measured the outgassing rate of an electropolished stainless steel surface after it was exposed to glow discharges fueled by various gases (He, He/1%-3%H{sub 2}, He/1%-3%CH{sub 4}, H{sub 2}, Ar) following a standard 1 h of venting to ambient air. It is shown that He GDC is most effective in reduction of outgassing rate: a He GDC trial with a dose of 0.8 C/cm{sub 2} reduces the outgassing rate and subsequently the pump-down time by a factor of 13. For given glow discharge currents, the outgassing reduction factor is directly proportional to the glow discharge duration. The reduction of post-GDC outgassing is a result of enhanced desorption of H{sub 2}, CO, and CO{sub 2} by He GDC as observed by residual gas analysis during the discharge. The GDC results are consistent with our previously proposed diffusion models for water outgassing from metal surfaces.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 801734
• Report Number(s): CEBAF-PR-94-010; DOE/ER/40150-2219
• Journal Information: Journal of Vacuum Science Technology A, Journal Name: Journal of Vacuum Science Technology A Vol. 13
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIR
CLEANING
DEGASSING
DESORPTION
DIFFUSION
GAS ANALYSIS
GASES
GLOW DISCHARGES
STAINLESS STEELS
VACUUM SYSTEMS
WATER