Overview of the Insertable B-Layer (IBL) Project of the ATLAS Experiment at the Large Hadron Collider at CERN

The ATLAS experiment will upgrade its Pixel Detector with the installation of a new pixel layer in 2013/14. The new sub-detector, named Insertable B-Layer (IBL), will be installed between the existing Pixel Detector and a new smaller diameter beam-pipe at a radius of 33 mm. To cope with the high radiation and hit occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed and are currently under investigation and production for the IBL. Furthermore, the physics performance should be improved through the reduction of pixel size while targeting for a low material budget, pushing for a new mechanical support using lightweight staves and a CO2 based cooling system. An overview of the IBL project, the results of beam tests on different sensor technologies, and testing of pre-series staves made before going into production in order to qualify the assembly procedure, the loaded module electrical integrity, and the read-out chain will be presented.