Vertex Detector

  A detector in collider experiments positioned as close as possible to the collision point. It is ypically made of cylindrical layers, positioned at radii of a few centimetres, the innermost layers preferrably with pixel readout. The goal of a vertex detector is to measure particle tracks very close to the interaction point (inner radii of a few cm, close to the beam pipe), thus allowing one to identify those tracks that do not come from the vertex (e.g. as a signature for short-lived decaying particles). Most vertex detectors seem to be made of semiconductor detectors, but precise drift chambers have also been used successfully, see [Abachi94].