[time-nuts] Maser info (vacuum levels)

[jimlux]

Heathkid wrote:
> Sounds like the parts of a "salvaged" SEM would be a good start for a 
> project such as this (assuming the diffusion pump is included - I've 
> been looking for one for a while but it seems the pumps are almost 
> *always* missing).  But still, if you could find one locally (freight is 
> $$$) there are a lot of very good, high precision parts just begging to 
> be "hacked".
> 
>
I haven't checked recently, but used/rebuilt diff pumps used to be 
really, really cheap (because everyone using them in a process situation 
was going to turbos, etc.).  Sure, you might wind up buying a whole 
pallet load of them, and half would be gunked up with some weird toxic 
carbonized slime, but those you just pitch.  Some of the others would 
have a heater that's broken, but you cannibalize off another one.  They 
have the virtue of simplicity..

I've always thought that it might not be that hard to hack a turbo 
pump.. I used to see the pump heads are readily available for cheap, 
it's the 3 phase inverter/motor drive that's expensive, but with modern 
VFDs maybe something could be hacked.  (yes, it's a different set of 
problems than a diff pump.. choose your poison?)