Design and simulation of the CMS first-level muon trigger track finder

The Large Hadron Collider LHC is scheduled to start operation in the year 2005 at the CERN research center. Experiments at this collider will look for extremely rare physics events hidden in an overwhelming rate of background events. It is the task of the experiment's trigger system to reduce the total event rate to a level that can be recorded permanently for later analysis. The high reduction factor from total rate to recording rate places demands on the experiment's trigger system that go beyond any experienced at previous high-energy physics experiments. The objective of my thesis has been to design a part of that trigger system, the regional first level muon trigger, of one of the LHC experiments, the Compact Muon Solenoid (CMS) detector. At the beginning, I give a brief introduction to the LHC and its physics motivation, followed by an overview of the CMS detector. The emphasis is on the detector's muon system. Next comes a general introduction to triggering, followed by an overview of the CMS trigger system. The next part addresses the specifications of the part of the trigger I have been working on. I describe how that device is embedded into the CMS first level trigger and specify its input and output quantities. That is followed by a discussion of the requirements placed on the regional muon trigger with respect to the general trigger requirements. The environment in which the trigger has to operate is described, giving the particle rates to which the muon system is exposed and detailing the impact of the detector's magnetic field and material on the particles' trajectories. I then review several methods and techniques employed in previous and existing muon triggers. The conclusion is that none of them meets the requirements stated before. For that reason a novel algorithm had to developed. I describe that algorithm in detail and present suggestions for implementing the algorithm in hardware. That is followed by a study of the algorithm's feasibility, and I show that the algorithm is feasible and fulfills the requirements. To assess the performance of this algorithm, I created a detailed software simulation, of which a brief overview is given. Finally, I present the performance as obtained by simulation.