Cloud chamber
A device to visualize passing radiation
A cloud chamber is a century-old particle detector. Alcohol vapor sinks from the top toward a very cold plate at the bottom, and just above the plate it becomes supersaturated. When a charged particle passes through that layer it ionizes the air along its path, leaving a short-lived trail you can see.
I wanted to build one that could be spun up on demand, rather than needing a short lived cooling method like dry ice. A clear dome over a machined base, a wire mesh screen near the top on three standoffs, and the cold plate and cooling stack below. The base carries the cold plate and seals against the dome. Underneath, a thermoelectric cooler pulls heat out of the plate and dumps it into a chiller loop.
