After more than two years of maintenance and upgrade during the LHC shutdown, the pixel detector in the center of the CMS detector was re-installed.
The CMS group at UZH together with colleagues from PSI, ETH and other institutes has been a major player in this endeavour. The innermost layer of the CMS pixel detector, which due to its location closest to the interaction point is exposed to the highest radiation, has been replaced with new modules featuring new readout chips and front-end ASICs. Additional refurbishment and repair of faulty components and connectors allowed to establish a working fraction among the 124 million readout channels of the pixel detector of more than 99%. Calibrations and cosmic data taking is currently ongoing and the CMS pixel detector is ready to record the first collisions during the LHC pilot run at the end of October.