Drift Chamber

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Cross-section view of the PHENIX detector

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The frame of the Drift Chamber

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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 p_T . A detailed description about PHENIX Drift Chambers (DC) can be found in the following publication.

Publications

• Low-mass Drift Chambers of the PHENIX central spectrometers at RHIC    (NIM A 494, 2002, doi.org/10.1016/S0168-9002(02)01464-X)
• PHENIX Central Arm Tracking Detectors    (NIM A 499, 2003, doi.org/10.1016/S0168-9002(02)01952-6)

Presentations

•    PHENIX Focus: The PHENIX Drift Chamber (Sergey Butsyk)

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

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