supercooling

[Hal Feinstein]

I know that radio astronomers often supercool some of their receiving 
equipment to lower the
noise  and thereby improve its sensitivity.  As a thought  experiment, 
would it be practical for a ham
to supercool parts of  the receiving chain of a system that was built to 
receive a very weak signal?
I'm thinking that the equipment, for example a low noise converter, 
could be placed into some kind of protective jacket and emersed in some 
supercool O2 or CO2 (dry ice).  First, does it make sense from a radio 
engineering/physics point fo view?   Second, is their a practical way to 
do this without elabroate equipment.   Third, anyone in the amateur 
community tried this?

--hal  wb3kdu