An introduction by Dr. Seog Oh

ATLAS is an experiment to search for the origin of mass and to study beyond the standard model. The experiment utilizes LHC (Large Hadron Collider) at CERN (European Center for Nuclear Research). The experiment will begin its data taking in year 2008.

The center of mass energy of LHC is 14 TeV, about 7 times higher then the most powerful present collider at Fermi National Lab. In the accelerator two proton beams circulate in opposite direction, which collide at several intersection regions.

Our main contribution for the experiment was to construct a part of the ATLAS detector, namely the Transition Radiation Tracker (TRT).

The TRT is a part of the Inner Detector and it occupies radii between ~60 cm and ~110 cm and +/- 200 cm in z. The system consists of more than 370,000 straws. The TRT consists of three different sections - two endcap detectors with radial straws and one barrel detector with straws oriented parallel to the magnetic field direction. Hence, the barrel TRT measures r-phi while the endcap TRT measures phi-z.

There are two functions of the TRT. One is to provide the tracking (of charged particles) and the other is to identify high energy electrons using transition radiation. The basic elements of the detector is 4 mm diameter thin wall (60 microns) straws and polyethylend foils (endcap TRT) or polypropylene-polyethylene fibers (barrel TRT) between straws.

The Duke group was involved with the Barrel TRT from the conceptual design stage, which led to the prototype module construction and testing . With the successful beam test of the prototype modules, the Barrel TRT module construction started in May 2000, and took about four years to complete. The finished modules were shipped to CERN for integration with the Silicon Detector and the combined detector was lowered to the experimental area for the final commissioning. Presently the detector is ready for proton and proton collisions.

Follow this link to see real events recorded in Barrel TRT .