Drift Chamber

Cross-section view of the PHENIX detector

The frame of the Drift Chamber

Detector Overview

The PHENIX drift chamber was a multiwire gaseous detector located at a radial distance of 2.02 < R < 2.48 m. There was one chamber on each arm, and they were mirror copies of each other, each one subtending 90° in azimuth and 2 m along the z direction. The DC measured the trajectories of charged particles in the r-φ plane in order to determine their charge and transverse momentum pT . A detailed description about PHENIX Drift Chambers (DC) can be found in the following publication.



Variables and Accessors under PHCentralTrack Node

   Type    Name    Description
   int    get_npart    Total number of tracks/particles in a givem event
   short    get_quality    Quality of the Drift Chamber tracks
   float    get_zed    z coordinate at which the track crosses PC1
   float    get_phi    phi coordinate at which the track crosses the drift chamber reference radius
   float    get_alpha    Inclination of the track w.r.t. an infinite momentum track. Hence, pT is roughly proportional to 1/alpha. This value comes from the straight line fit and does not respect residual bends
   float    get_beta    This is essentially the spherical coordinate "THETA" of the track vector as it passes through the drift chamber reference radius
   float    get_phi0    Track's phi direction at the vertex
   float    get_the0    Track's theta direction at the vertex
   float    get_mom    Magnitude of the momentum
   float    get_px    Momentum along X-direction
   float    get_py    Momentum along Y-direction
   float    get_pz    Momentum along Z-direction
   float    get_E    Energy estimated using DC
   short    get_charge    Returns charge of the track