Spark Chamber

       A Spark chamber consists of a set of conducting plates alternately connected to a source of high DC voltage - Fig 1

Fig - 1

      The chamber is filled with an inert gas. Sudden application of very high voltages to alternate plates. While the other are left at ground potential. results in very high electrical fields across the gaps. Electrical breakdown then occurs along the trails of ions. So the trajectory of a given particle through the system is marked by a series of sparks. The spark trails are photographed stereoscopically. If the chamber is located in a magnetic field, the charge and momentum of the particle can be determined from the curvature of the track. Vidicons are frequently used in place of photography.

      The spark chamber has an important advantage over the bubble chamber in that it can be rendered sensitive for only a very short time. Suppose, for example, that in an intense beam from a high-energy particle accelerator a rather rare particle is produced. Scintillation or Cerenkov counters can signal the production of this kind of particle. The pulse voltage is then applied to the spark chamber. The track of this particular particle can thus be determined. There is little likelihood that one of the much more numerous background particle will cause another spark track in the short time that the chamber is sensitive. Thus rare events and processes can be studied.