Upgrades of the ATLAS Pixel Detector

The upgrade for the ATLAS detector will undergo different phases towards HL-LHC. The first upgrade for the Pixel Detector (Phase 1) consists in the construction of a new pixel layer, which will be installed during the 1st long shutdown of the LHC machine (LS1) in 2013/14. The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of about 3.2 cm. The IBL requires the development of several new technologies to cope with the increase of radiation and pixel occupancy as well as to improve the physics performance of the existing pixel detector. The pixel size is reduced and the material budget is minimized by using new lightweight mechanical support materials and a CO2 based cooling system. For Phase 2 upgrade of LHC a complete new 4-layer pixel system is planned as part of a new all silicon Inner Detector. The increase in luminosity to about $5\cdot 10^{34}$cm$^{-2}$s$^{-1}$ together with a total expected lifetime of about 3000fb$^{-1}$ sets un-preceded requirements on the innermost pixel layers exceeding the current ones by roughly one order of magnitude in terms of particle rate, fluence and TID. Thus, new technologies must be developed and tested, among these are as well hybrid pixel detector concepts and monolithic approaches. An overview of the different upgrade projects with particular emphasis on the IBL layout, specifications, performance and developments for future pixel detector concepts are presented.