Robustness studies of the CMS tracker for the LHC upgrade phase I

Currently, several changes are being implemented in the tracker geometry of the Compact Muon Solenoid (CMS). These should improve the performance of both strip and pixel detectors. The new pixel detector will have four barrel pixel layers and three disks in the ends, compared to the current configuration of three barrel pixel layers and two disks in the ends. Also the material used to make these additional layers and disks has been reduced, yielding a lighter pixel detector and therefore, reduces the interaction of particles with the inactive material in the tracker. All these improvements are included in the CMS software (CMSSW) that simulates the response of the detector in scenarios such as increased luminosity in the Large Hadron Collider (LHC) for the period known as Phase 1 upgrade. In this thesis, I perform some studies to show the robustness of the upgraded de- tector with respect to the present detector. These studies consider two scenarios with inefficiencies in the outer tracker; degradation of the first two silicon TIB layers (which are those closer to the pixel detector), and failures in some tracker modules of the outer tracker (Tracker Inner Barrel (TIB), Tracker Outer Barrel (TOB) and Tracker Inner Disk (TID)) that are believed to possibly become unstable at increasing luminosity. Fi- nally, we study a third scenario which shows the preliminary results of a new method for simulating radiation damage on the first layer of the pixel detector.