Outgassing and desorption of the stainless steel beam tubes after different degassing treatments
Chemical cleaning, vacuum firing, glow discharge cleaning and insitu bakeout have become standard practice for lowering the outgassing rate and removing surface contaminants in the ultra high vacuum systems of particle accelerators and storage rings. This paper presents the work done with the thermal outgassing of several long stainless steel (304LN and 316L) beam chambers with areas of more than 1 x 10/sup 4/ cm/sup 2/. They were measured between 20/degree/ C and 500/degree/ C after vacuum firing, glow discharge cleaning or reactive gas (nitric oxide) cleaning. Outgassing rates of low 10/sup -13/ and low 10/sup -14/ Torr .1/s.cm/sup 2/ were achieved for H/sub 2/ and CO, respectively, with vacuum firing alone. The outgassing of H/sub 2/ in this temperature range is consistent with that due to bulk diffusion with an enthalpy of 9 +- 1 Kcal/mole. The photon stimulated desorption of the chamber surface after the above treatments were also studied by exposure to an intense photon beam at the National Synchrotron Light Source. The effectiveness and merits of reactive gas cleaning in removing the surface contaminants in large vacuum systems are compared to those of vacuum firing and glow discharge cleaning. 14 refs., 5 figs.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 7010163
- Report Number(s):
- BNL-41181; CONF-881002-14; ON: DE89001268
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420200 -- Engineering-- Facilities
Equipment
& Techniques
43 PARTICLE ACCELERATORS
430300* -- Particle Accelerators-- Auxiliaries & Components
ACCELERATORS
ALLOYS
CHROMIUM ALLOYS
CLEANING
CONTAINERS
CORROSION RESISTANT ALLOYS
DEGASSING
IRON ALLOYS
IRON BASE ALLOYS
PRESSURE VESSELS
STAINLESS STEELS
STEELS
STORAGE RINGS
SURFACE CLEANING
SURFACE FINISHING
TUBES
VACUUM SYSTEMS