> On Sep 30, 2022, at 11:19 PM, Tom Hunter <ccth6...@gmail.com> wrote:
>
> https://www.stirlingcryogenics.eu/
>
> These machines are still made and indeed are very cool. ;-)
So to speak!
I didn't see their liquid helium machine. I remember one installed at the TU
Eindhoven physics department; it consisted of a pair of two-stage Stirling
machines (which by themselves will liquify hydrogen or neon, i.e., they go down
to about 20 K) plus a bunch of auxiliary equipment. The whole setup took maybe
a 15 foot square room.
The website doesn't show any of the compact machines I remember seeing
described. A bunch of those had 400 Hz power, indicating they were meant for
airborne use. One was a little lab bench machine, a box perhaps the size of an
old style desktop PC, lying flat, with a "cold finger" sticking out of the box.
paul
