ATLAS Experiment CERN

Inner Detector

The ATLAS Inner Detector combines high-resolution detectors at the inner radii with continuous tracking elements at the outer radii, all contained in the Central Solenoid, which provides a nominal field of 2 T. The highest granularity is achieved around the vertex region using semiconductor pixel detectors followed by a silicon microstrip detector. Typically for each track the pixel detector contributes three and the strips fours space points. At larger radii typically 36 tracking points are provided by the straw tube tracker. The relative precision of the measurement is well matched, so that no single measurement dominates the momentum resolution. The outer radius of the Inner Detector is 1.15 m, and the total length 7 m. In the barrel region the high-precision detectors are arranged in concentric cylinders around the beam axis, while the end-cap detectors are mounted on disks perpendicular to the beam axis. The barrel TRT straws are parallel to the beam direction. All end-cap tracking elements are located in planes perpendicular to the beam direction.


Other Inner Detector Sections

General | Pixel Detector | SCT | TRT

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