Fast and radiation hard silicon detectors for the LHC-b Upgrade II

High radiation tolerance will be a key prerequisite for the vertex detectors in future hadroncollider experiments such as the LHCb Upgrade II. It is therefore of utmost importance to understand the effects radiation has on the sensor performance and how they can be mitigated. The main scope of this thesis is the study of planar hybrid silicon sensors in the fluence range of the LHCb Upgrade II using measurements combined with TCAD simulations to understand the sensor behaviour at these fluences and provide possible detector scenarios for further radiation reduction. Several test structures with a thickness of 50, 100, 200 and 300 µmrespectively were produced and characterised before irradiation by IV and CV measurement. The results were compared to simulations and used to validate the used sensor model for further simulations. A comprehensive radiation campaign with proton and neutron irradiation was done covering a fluence range from 1 × 1015 neq cm=2 to 1 × 1017 neq cm=2. After irradiation the change of leakage current and sensor signal was studied as a function of thickness and fluence. All measurements were compared to simulation using a state-of-the art radiation damage model. In addition, a fast simulation tool was developed to study possible new detector layouts and validate their performance, in particular in terms of impact parameter resolution. Using this tool, alternative detector layouts were proposed, which would reduce the radiation damage of all sensors in the detector. An extensive discussion of the impact of the RF-foil on the impact parameter resolution of the detector is also presented. iii