About the Image

The image to the right is an artfully colored photograph of charged particle tracks in a detector called a bubble chamber. The liquid, usually hydrogen, is brought to a superheated state (at a temperature above boiling) where the liquid can't change to gas without a seed of some kind for the bubbles to form on. A charged particle, through electromagnetic interactions, will cause atoms in its path to lose electrons and become ions. These ions become the seed of the small bubbles that mark the trajectories of the subatomic particles.

       

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The tracks are curved due to the presence of a magnetic field. The amount of curve to each track depends on the speed and mass of the particle and the strength of the magnetic field. In the two panels to the right we see an original bubble chamber photo and the reconstructed physics of an Omega minus particle produced by the collision of a K minus with a proton from the hydrogen. The Omega minus then decays into an array of particles, some of  which subsequently also decay. Some of the decay products of the Omega minus are not charged (dashed lines) thus do not produce ions or bubbles, but are given away when they decay to a pair of charged particles. 

© 2008 Raymond E Hall



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