A ug 2 00 5 The ATLAS Pixel Detector
The ATLAS Pixel Detector is the innermost layer of the ATLAS tracking system and will contribute significantly to the ATLAS track and vertex reconstruction. The detector consists of identical modules, arranged in three barrels concentric wi th the beam line and centered on the interaction point and three dis ks on either side for the forward region. The position of the Pixel Detector near the interaction point requires excellent radiation hardness, mechanical and the rmal robustness and good long-term stability, all combined witha low material budget. The detector layout, results from production modules and the status of assembly are presented.
Design studies on sensors for the ATLAS Pixel Detector
For the ATLAS Pixel Detector, prototype sensors have been successfully developed. For the sensors design, attention was given to survivability of the harsh LHC radiation environment leading to the need to operate them at several hundreds of volts, while maintaining a good charge collection efficiency, small cell size and minimal multiple scattering. For a cost effective mass production, a bias grid is implemented to test the sensors before assembly under full bias.
Results on 0.7% X0 thick pixel modules for the ATLAS detector
Abstract Modules are the basic building blocks of the ATLAS pixel detector system, they are made of a silicon sensor tile containing ∼46 000 pixel cells of 50 μm×400 μm, 16 front-end chips connected to the sensor through bump bonding, a kapton flex circuit and the module controller chip. The Pixel detector is the first to encounter particles emerging from LHC interactions, minimization of radiation length of pixel modules is therefore very important. We report here on the construction techniques and on the operation of the first ATLAS pixel modules of 0.7% radiation length thickness. We have operated these modules with threshold of 3700×10±300×10, mean noise value of 225×10 and 0.3% dead channels.