This is a bubble chamber picture from the CERN 2 metre-long bubble chamber that is filled with liquid hydrogen—a clean source of proton targets (no neutrons). The chamber is exposed to an incoming parallel beam of negative kaons (к-) with energy of 8.2 GeV, entering from the bottom of the picture.
The picture contains examples of many characteristic features that need to be recognized if one is to be able to interpret such pictures. In particular:
During this tutorial, a cleaned-up version of this picture will be used. (Click on picture, then move cursor over A or B to activate.)
All tracks that are not associated with the parallel beam are background and will be removed from subsequent pictures. (Move cursor to active area B)