Tracking Detector

The tracking detctor works on the principle that a charged particle ionises gas when is passes through it. Tracking detectors consist of chambers that contain thousands of thin wires surrounded by a suitable gas. Some of these wires (anodes) are sense wires and the rest are cathodes to create an electrostatic field. When a charged particle ionises the gas surrounding the wires, the resultant electrons and ions drift towards the respective wires and produce a signal. The signals produced by the detector during an event can be used to reconstruct the paths the particles took through the chamber..

	This picture illustrates the principle operation of the tracking detector. Outside of the detector a large soilenoid creates a magnetic field within the chamber which causes the charged particle paths to bend. The nature of this bending can be used to identify the charge and momentum of the particle track. This is expained fully in the event display section.
This picture shows the central tracking detector being lowered into place within the ZEUS detector.