2. The DELPHI Detector

The DELPHI^2.1detector is one of four [13,14,15,16] installed around the LEP^2.2electron-positron collider at CERN.^2.3For its first seven years LEP operated at around 91 GeV centre-of-mass energy (the $\ensuremathbox{\mathrm{Z^0}}$ resonance). At the end of 1995 it made a brief foray to 136 GeV. From July 1996 it has been mostly been running above the $\ensuremathbox{\mathrm{W^+ W^-}}$ threshold, initially at 161 GeV. In this thesis I describe the detector configuration and experimental results from the period of $\ensuremathbox{\mathrm{Z^0}}$ running.

DELPHI is designed as a general purpose detector with special emphasis on particle identification (using the Ring Imaging Cherenkov (RICH) detector) and precise measurement of particle decays close to the collision point (using the silicon Vertex Detector (VD)).