Developments of the ATLAS pixel detector

The ATLAS silicon pixel detector is the innermost tracking device of the ATLAS experiment at the Large Hardon Collider, consisting of more than 1700 modules for a total sensitive area of about 1.7 m 2 and over 80 million pixel cells. The concept is a hybrid of front-end chips bump bonded to the pixel sensor. The elementary pixel cell has 50 μ m × 400 μ m size, providing pulse height information via the time over threshold technique. Prototype devices with oxygenated silicon sensor and rad-hard electronics built in the IBM 0.25 μ m process have been tested and maintain good resolution, efficiency and timing performances even after receiving the design radiation damage of 10 15 n eq / cm 2 .