A bubble chamber photographs vapor bubbles along charged particle paths in a transparent superheated liquid. The liquid serves as target and recording medium.[ref]
How It Works: Bubble Chamber (CERN teaching archive). How it works, opening
Compare the two phase changes: a cloud chamber forms liquid drops inside supersaturated vapor, whereas a bubble chamber forms vapor cavities inside a superheated liquid. Both use metastability to amplify a microscopic disturbance. The photons reaching the camera reveal the drops or bubbles. The photographed trail's width is not the particle's width: it includes bubble growth, illumination and spatial resolution.
