- an apparatus for determining the movements of charged particles, consisting of a chamber containing a superheated transparent liquid that, by boiling and producing bubbles in the path of an ionizing particle, indicates the path of the particle.
- a device that enables the tracks of ionizing particles to be photographed as a row of bubbles in a superheated liquid. Immediately before the particles enter the chamber the pressure is reduced so that the ionized particles act as centres for small vapour bubbles
