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The Transition Radiation Tracker (TRT) sits at the outermost part of the ATLAS Inner Detector, encasing the Pixel Detector and the Semi-Conductor Tracker (SCT). The TRT combines charged particle track reconstruction with electron identification capability. This is achieved by layers of xenonfilled straw tubes with periodic radiator foils or fibers providing TR photon emission. The design and choice of materials have been optimized to cope with the harsh operating conditions at the LHC, which are expected to lead to an accumulated radiation dose of 10 Mrad and a neutron fluence of up to 2 10 14 n/cm 2 after ten years of operation. The TRT comprises a barrel containing 52 000 axial straws and two end-cap parts with 320 000 radial straws. The total of 420 000 electronic channels (two channels per barrel straw) allows continuous tracking with many projective measurements (more than 30 straw hits per track). The assembly of the barrel modules in the US has recently been completed, while the end-cap wheel construction in Russia has reached the 50% mark. After testing at the production sites and shipment to CERN, all modules and wheels undergo a series of quality and conformity measurements. These acceptance tests survey dimensions, wire tension, gas-tightness, high-voltage stability and gas-gain uniformity along each individual straw. This paper gives details on the acceptance criteria and measurement methods. An overview of the most important results obtained to-date is also given.

Abstract--The Transition Radiation Tracker (TRT) is one of three particle tracking detectors now under construction for the ATLAS experiment, whose goal is to exploit the highly exciting new physics potential at CERN's next accelerator, the so called Large Hadron Collider (LHC).The TRT consists of 370000 straw proportional tubes of 4 mm diameter with a 30 micron thick anode wire, which will be operated with a Xe/CO 2 /O 2 gas mixture at a high voltage of approximately 1.5 kV. While the construction of the TRT is now well under way, a number of interesting and challenging questions need to be solved with regard to wire aging phenomena, which are induced by pollution originating from very small amounts of silicon-based vacuum materials in some components of the gas system. Finally a guideline to avoid aging in wire chamber detectors in high luminosity experiments is given.

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