Lessons learned in the ATLAS Pixel IBL project

The ATLAS experiment is ready to face the Run-2 of the Large Hadron Collider at CERN with improved tracking performance thanks to the installation of a new Pixel layer, also called Insertable B-Layer (IBL). The IBL has been installed in May 2014 being placed at only 3.3 cm radius from the beam axis. The combination of the limited distance from the interaction point and the increase of Luminosity that LHC will face in Run-2 will require to cope both with higher radiation environment and pixel occupancy.Two different silicon sensor technologies (planar and 3D) have been developed and a new readout chip within CMOS 130nm technology with larger area, smaller pixel size and faster readout capability. Dedicated design features in combination with a new composite material were considered and used in order to reduce the material budget of the support structure while keeping the optimal thermo-mechanical performance. Due to the limited radial space about less than 1 cm, the IBL detector was a challenge in terms of design and mechanical integration. An overview of the lessons learned during the IBL project will be presented, focusing on the challenges and highlighting the issues met during the production, integration, installation and commissioning phases of the detector. Early performance tests using cosmic ray and beam data will also be presented.