Masoud,

I've cooled objects in vacuum chambers to ~80K with very little cost and time.

Do you have a spare port on this chamber, and is it larger than 30mm in diameter?

If so, then I would suggest fabricating a feed-though. Take a flange, drill two holes through it, and pass a loop of copper pipe through the holes. Braze the copper in place (propane torch and silver-loaded spelter) and run water through the pipe. A bucket and a fountain pond pump are sufficient to drive the water.

I've done this on two chambers, and used liquid nitrogen on a third using the same technique. Either KF or CF flanges lend themselves to this sort of work well - I've used both CF40s and large KFs to make water and LN2 feedthroughs.

Or, and this is not as much fun, simply buy a liquid feedthrough from Kurt Lesker or any other vacuum stockist.

A warning about what James said: If you have a flange that is repeatably cooled and warmed, the combination of condensation and temperature cycling will accelerate the corrosion of the Cu gasket. I had a leak after 4 months. Make sure to use a Au coated gasket.

Jonathon,

If the loop is carrying only water, there ought not to be much temperature cycling.

A cryogenic feed is another matter and I'd strongly suggest a bought item for the beginner.

If Masoud if building it himself, yes, even a nice tight (bright) brazed joint is not as strong as a weld and might be cracked or damaged more easily. Mind. a Lesker product (or MDC Caburn) would be all stainless and probably bullet-proof.

But your remark, of general concern for corrosion and water condensation is a good reminder to all to be aware of proper precautions when dealing with liquids.

James,

Yes I should have been more clear. In my case the loop was carrying LN2. I too would suggest a bought item or a UHV experienced machine shop, and installed with a Au coated gasket.

PVD products has delivered many water cooled, LN2 cooled stages with and without RF bias and rotation.   They are very easy to make but require the proper chamber design.  We have used brazes, welds, and VCR fittings without any issues for many years.