The ATLAS TRT barrel detector

The ATLAS TRT barrelis a tracking drift chamber using 52,544 individual tubular drift tubes. It is one part of the ATLAS Inner Detector, which consists of three sub-systems: the pixel detector spanning the radius range 4 to 20 cm, the semiconductor tracker (SCT) from 30 to 52 cm, and the transition radiationtracker ( TRT) from 56 to 108 cm. The TRT barrelcovers the central pseudo-rapidity region |eta| < 1, while the TRT endcapscover the forward and backward eta regions. These TRT systems provide a combination of continuous tracking with many measurements in individual drift tubes ( or straws) and of electron identificationbased on transition radiationfrom fibers or foils interleaved between the straws themselves. This paper describes the recently-completed construction of the TRT Barreldetector, including the quality control procedures used in the fabrication of the detector.