[Sneap] Turbo pumps and cesium

[Klaus Bahner]

Hi Powell,

Thank you for your reply. I reckon then that cesium and other alkaline
metals are a real world issue. I hoped it was just a theoretical concern :-(

> It's crude, but it works.  I suppose if one were starting 
> over, a corrosive pump model might be employed to obviate 
> these sorts of issues.

Well, the pump we are going to use *is* a corrosion resistant, semiconductor
pump, still the manufacturer considers alkaline metals a potential problem.
So, I'm afraid this is not the final answer.

Leaves the question, whether it would help to run the pump at elevated
temperatures (kind of baking system) in order to prevent condensing. That
probably boils down to the question, what is cesium's vapour pressure at
reasonable pump temperatures. Does anyone know where to look for a  vapour
pressure/temperature curve under vacuum conditions for cesium?


Klaus