The ATLAS Insertable B-Layer

During the first shutdown of LHC, the ATLAS detector is undergoing an upgrade of the Pixel Detector in preparation for high luminosity LHC. This upgrade consists of a new pixel layer, called the Insertable B-Layer (IBL), which is positioned between the former inner layer of the Pixel Detector (B-Layer) and a new, smaller, beam pipe, at a radial distance of 3.3 cm from the beam axis. The realization of the IBL required the development of several new technologies and solutions in order to overcome the challenges introduced by the extreme environment and working conditions, such as the high radiation levels, the high pixel occupancy and the need of an exceptionally low material budget. Two silicon sensor technologies have been adopted for the IBL modules: planar n-in-n and 3D. Both of these are connected via bump bonding to the new generation 130 nm IBM CMOS FE-I4 front-end read-out chip. An overview of the IBL project, module design, the qualification tests, data acquisition, results and performance is presented.