The LHCb SciFi Tracker: studies on scintillating fibres and development of quality assurance procedures for the SciFi serial production

For 2019 an upgrade of the LHCb detector is foreseen. The tracking stations behind the magnet will be replaced by a detector made of scintillating fibres with a silicon photomultiplier read out. To achieve a spatial resolution better than 100 µm, fibres with a diameter of 250 µm are accurately positioned in several layers and glued to 2.5 m long mats. To ensure a proper quality of these fibre mats quality assurance during the production of these mats is mandatory. This thesis presents quality assurance procedures which were developed for the serial production of the Scintillating Fibre (SciFi) Tracker. In the production scintillating fibres are wound on a threaded wheel. To directly check the winding procedure, a live monitoring setup including a software based on machine learning and image recognition has been developed. The introduced quality assurance procedures enabled a smooth running serial production with high quality fibre mats. An essential parameter to assess the quality is the light yield of a fibre mat. The mean light yield loss at the end of the nominal lifetime of the SciFi tracker obtained from simulations is about 35%. An in situ irradiation campaign in the LHCb cavern monitoring the radiation damage over time is presented in this thesis. The obtained results confirm results from simulations based on former irradiation campaigns