Ultrahigh vacuum system
Neutral pressure should be < 10-10 Torr
Stainless steel vacuum vessel
All in-vacuum components baked to 300 oC
- Stellarator coils will be cooled during bake
- High temp. bake eliminates water etc. Hydrogen remains.
- Hydrogen outgassing must be further reduced, e.g. by pre-baking the stainless steel in a vacuum furnace.
Hard copper gasket seals - no o-rings.
Oil free multiple stage pump system
- Ion pump with base pressure < 10-11 Torr and 150 liters/s
Due to restricted pump port access, the system is likely to be conduction limited - must be considered in the design