It's happening! The background radiation of the universe is all around us and this fully operational cloud chamber visualizes it.
The apparatus has been on the floor for several weeks now with fairly solid performance. I had to rip out a fair amount of rotten material and rebuild. This:
Add lights, it's getting there:
All told that was about 60 hours work, $400 in materials and an $800 bill from the refrigeration service tech for the one part of the job I couldn't do (there was a slight coolant leak in the condensor assembly).