The ATLAS Insertable B-Layer (IBL) Project.

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 radius beam-pipe at a radius of 3.3 cm. To cope with the high radiation and pixel 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. Furthermore, the physics performance should be improved through the reduction of pixel size while targeting for a low material budget should be imposed, pushing for a new mechanical support using lightweight staves and a CO2 based cooling system. An overview of the IBL project and the status of the two 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.