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Outgassing measurement of an LHC collimator and estimation for the NEG performances
- Source :
- Vacuum. 85:1178-1181
- Publication Year :
- 2011
- Publisher :
- Elsevier BV, 2011.
-
Abstract
- The outgassing rate of the collimators in the Large Hadron Collider (LHC) at CERN has an important role for the life-time of the Non-Evaporable Getter (NEG), and an accurate analysis allows the definition of future activities, like NEG vacuum activation. For these reasons, both, total outgassing rate and gas composition of a secondary collimator have been measured in the laboratory. The outgassing rate decreases by about two orders of magnitude by after bake-out and moreover, repeated bake-out further reduced the outgassing rate. The gas transmission through the NEG coated beam pipes and the resulting pressure distributions near the collimator were also measured in a dedicated setup. It is found that the main gas component after just 2 m of NEG coated beam pipe is CH 4 due to the extreme pumping speed of NEG for the other gases. Large amount of outgassing for H 2 and carbon related molecules are released when moving the collimator jaws. It is found that the NEG is very effective even in such case with large gas load.
Details
- ISSN :
- 0042207X
- Volume :
- 85
- Database :
- OpenAIRE
- Journal :
- Vacuum
- Accession number :
- edsair.doi...........ad11b455c476192178b3bc763027e565